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MAY7-19W

CLASS BOOK

OF

ECONOMIC ENTOMOLOGY

LOCHHEAD

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T. W.

Harris

Asa Fitch

TowNEND Glover

B. D. Walsh

C. V. Riley

W. Saunders J. Fletcher C. J. S. Bethune

Some Pioneer Workers in Economic Entomology.

Si

CLASS BOOK

^l^ OF

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ECONOMIC ENTOMOLOGY

WITH SPECIAL REFERENCE TO THE ECONOMIC INSECTS
OF THE NORTHERN UNITED STATES AND CANADA

BY

WILLIAM LOCHHEAD, B. A., M. S. (Cornell)

PROFESSOR OF BIOLOGY IN THE MACDONALD COLLEGE OF McGILL UNIVERSITY; F. A. A. S.

MEMBER OF THE ENT. SOC. OF AMERICA, AND THE AM. ASSOC. ECON. ENT.;

EX-PRESIDENT ENT. SOC. OF ONTARIO; PRESIDENT QUEBEC SOC. FOR

THE PROTECTION OF PLANTS, ETC.

WITE 257 ILLUSTRATIONS

PHILADELPHIA

BLAKISTON'S SON & CO.

1012 WALNUT STREET

Copyright, 1919, by P. Blakiston's Son & Co.

THE MAPX.H! FRBBS X O R K PA,

PREFACE

All teachers are agreed that the best results in the classroom are
secured only by the adoption of the best pedagogical methods, with
ready access to the necessary specimens and literature. Just what
these methods comprise, however, is, with many teachers, a matter of
opinion. Quot homines tot sententice, nevertheless the indulgent reader
may concede that an experience of over twenty years as a teacher of
economic entomology in agricultural colleges may warrant the voicing
of the author's conviction that instruction in this subject should con-
sist of (i) studies on the structure, metamorphosis, and bionomics of
insects, carried on both in the laboratory and in the field; (2) practice
in the classification and description of the more common insects in
their various stages; and (3) studies of the methods of control, with
practical exercises in the preparation and application of insecticides.

Although several most excellent manuals on Economic Entomology
have been published in recent years, there seems to be a need for a
book providing the necessary information for the student in the class-
room, laboratory and field along the lines indicated above.

This class-book, therefore, has been prepared to meet the needs of
the class-room instructor, and his needs have influenced the mode of
presentation of the subject material. It does not presume to take the
place of the invaluable and well-known works of Folsom, Comstock,
Slingerland and Crosby, and others; but rather, it aims to present such
material as will best help the student in acquiring a fair working knowl-
edge of the modern science of Economic Entomology.

The treatment of many of the topics is necessarily limited, and the
keys for the identification of orders, families, and genera make no pre-
tensions to completeness. The descriptions of the species discussed in
Part III are stripped of all unnecessary verbiage so that all the essential
facts of the life-histories may be included in the space at the author's
disposal.

VI PREFACE

Laboratory exercises have been omitted, as the intelligent teacher
is in a better position than the author to prepare practicums adapted to
local conditions.

It was thought advisable to limit the species discussed mainly to
those belonging to the Northern United States and Canada, i.e., to
the Canadian, Transition, and Upper Austral Zones. It was also
deemed advisable to make but brief mention of the insects affecting
forest trees. Students interested in such studies are referred to the
recent bulletins of A. D. Hopkins of Washington and J. M. Swaine of
Ottawa for the results of the latest investigations.

The author is indebted to many fellow-teachers and workers for valu-
able aid and suggestions in the preparation of this book. In most
respects it is a compilation from recent text-books, bulletins, and arti-
cles. In a work of this kind errors are likely to appear in spite of
every precaution, but considerable care has been taken to reduce them
to a minimum.

Special mention must be made of the kindness of many authors
and publishers in furnishing illustrations, and the writer here thanks
his friend and teacher. Professor J. H. Comstock of Cornell University,
for permission to use illustrations of wing- venation from his recent
work, "The Wings of Insects;" Dr. C. G. Hewitt, Dominion Entomolo-
gist, for free use of cuts from the publications of the Canadian Ento-
mological Branch; Dr. L. O. Howard, Chief of the U. S. Bureau of
Entomology, for many electrotypes of the Bureau illustrations; Pro-
fessor J. H. Sanders of the Pennsylvania Agricultural Experiment
Station, for permission to use his admirable figures of pygidia of scale
insects; Mr. J. J. Davis, Federal Agent of the U. S. Bureau of Entomol-
ogy, Lafayette, Indiana, for several photographs of breeding cages,
etc.; Professor L. Caesar of the Ontario Agricultural College, and Dr. S.
Hadwen, Dominion Pathologist, Health of Animals Branch, Ottawa,
for furnishing several cuts; Mr. Arthur Gibson, Entomological Branch,
Ottawa; Professor W. H. Brittain of the Truro Agricultural College;
Professor P. J. Parrott of the New York Agricultural Experiment
Station; Professors Herrick, Crosby and Johannsen of Cornell Univer-
sity; Professor W. A. Riley of the Minnesota Agricultural College; Dr.
Edith Patch of the Maine Agricultural Experiment Station; Professor
W. E. Britton of the Connecticut Agricultural Experiment Station;
Professor V. L. Kellogg of the Leland Stanford Jr. University, Professor

PREFACE Vll

W. B, Herms of the University of California; and the MacMillan Co.,
the Comstock PubHshing Co., Henry Holt and Co., and P. Blakiston's
Son and Co., for permission to use certain illustrations from their
entomological publications.

To Mr. E. M. DuPorte, M. Sc, of Macdonald College, the author is
specially indebted for the drawings illustrative of the structure of
insects in Part I, for valuable criticisms, and for substantial help in
proof-reading.

W. LOCHHEAD.
Macdonald College.

CONTENTS

INTRODUCTION

PART I— THE STRUCTURE, GROWTH AND ECONOMICS
OF INSECTS

Page

The Branch Arthropoda i

The Class Insecta 2

Structure of Insects 2

External Anatomy 2

Internal Anatomy 19

The Development of Insects 30

Embryology, Metamorphosis — stages 30

Losses due to Insects 38

Beneficial Insects 39

Insects and Birds 44

Insects and Plants 45

Insects as Plant Disease Carriers 46

Insects and Disease 49

Insect Behavior toward Stimuli 57

Relation of Insects to Temperature and Humidity 59

Distribution of Insects 60

Methods of Studying Economic Insects 64

PART II.— THE IDENTIFICATION OF INSECTS INJURIOUS TO
FARM, GARDEN AND ORCHARD CROPS, ETC.

Insects injurious to Cereal Crops 71

Insects injurious to Indian Corn or Maize 72

Insects injurious to Clover and Alfalfa ' 73

Insects injurious to Peas and Beans 74

Insects injurious to Stored Grain Products 74

Insects injurious to Root Crops 76

Insects injurious to the Potato Crop 76

Insects injurious to Garden Vegetables 77

Insects injurious to the Apple 77

Insects injurious to the Plum 80

Insects injurious to the Cherry 82

Insects injurious to the Peach 83

Insects injurious to the Raspberry and Blackberry 83

Insects injurious to the Gooseberry and Currant 84

ix

X CONTENTS

Pace

Insects injurious to the Grape 85

Insects injurious to the Strawberry 86

Insects affecting Shade Trees 87

Insects injurious to Greenhouse plants 90

Insects affecting Domestic Animals 90

Insects of the Household 92

PART III.— CLASSIFICATION AND DESCRIPTION OF COMMON

INSECTS

Common Orders 93

Aptera group 94

Thysanura 95

Neuropteroida group 96

Mallophaga 100

Orihopteroida group 102

Isoptera 102

Corrodentia 103

Blattoidea 103

Mantoidea 105

Dermaptera 106

Phasmoidea 106

Orthoptera 107

Thysanoptera 118

Homoptera 122

Hemiptera 158

Siphunculata 167

Lepidoptera 169

Diptera 239

Siphonaptera 279

Coleoptera 280

Hymenoptera 343

Invertebrates other than Insects 363

PART IV.— THE CONTROL OF INJURIOUS INSECTS

Factors of Insect Control 373

Methods of Control 374

The Action of Insecticides 400

Utilization of Parasitic Insects 401

Bibliography 407

Glossary . . . . 409

Index 415

INTRODUCTION

'Economic Entomology is that phase of Entomology which relates
to the control of injurious insects. Its scope is much wider than that of
applied entomology, for the latter, properly speaking, is the application
of the principles that have been formulated by the economic entomolo-
gist as a result of his investigation of insects and their relations to their
environment. Its scope embraces a study of the structure, habits and
life-histories of the injurious insects and of their relations to all the
natural and artificial conditions to which they may be subjected. It
also includes the investigation of the nature of the losses and the prac-
ticable means by which they may be prevented or lessened.

Considering the great variety of insect forms, their diverse methods
of food habits, the large number of kinds of hosts which supply them
with food, and the enemies which tend to destroy them, it becomes
evident that the problem of insect control is most complex. As
Professor Forbes says: " The subject matter of this science is not insects
alone, nor plants alone, nor farming alone. One may be a most ex-
cellent entomologist or botanist, or he may have the whole theory and
practice of agriculture at his tongue's end, and at his fingers' end as well,
and yet be without knowledge or resources when brought face to face
with a new practical problem in economic entomology. The subject is
essentially the relation of these things to each other; of insect to plant
and of plant to insect, and of both of these to the purposes and opera-
tions of the farm, and it involves some knowledge of all of them."

The Rise of Economic Entomology

The records of the rocks reveal the existence of insects at an early
period in the world's history, long before man made his appearance.
Early historic records also show clearly that not only man himself but
also his crops and flocks sufifered from insect attacks. The ravages of
locusts, canker worms and palmer worms are frequently described in
graphic language by the Old Testament prophets.

Xll INTRODUCTION

In America, too, before the advent of Europeans, the Indians were
acquainted with insects that injured their corn fields, and during the
seventeenth and eighteenth centuries the crops of the early settlers were
seriously ravaged by "canker worms" and grasshoppers. One may say,
therefore, with Webster: "the actual economic element in entomology
is inevitably as old as Agriculture itself." On account, however, of the
ignorance and superstition that prevailed even among the learned
classes regarding the nature and habits of insects, no progress in the
control of insect pests was made or was possible until the latter half of
the nineteenth century. The introduction of rational methods of
control had to wait until considerable advance had been made in the
classification of insects and in a knowledge of their structure, habits and
life-history.

In so far as America is concerned, it may be said that outbreaks of
certain insects, viz., the Rocky Mountain locust, the cotton worm
and the Colorado potato beetle during the last quarter of the nineteenth
century produced wide-spread attention to the great losses caused by
them, and forced the U. S. government at that time to appoint a
commission of entomological specialists for the purpose of investi-
gating the conditions. It was during this period that some of the
modern insecticides and improved spraying machinery were introduced,
Paris green becoming the standard remedy against the Colorado
potato beetle and the cotton worm, and kerosene emulsion against
sucking insects. The reports of Harris, Fitch and Riley, especially
those on the Rocky Mountain locust laid the foundation for future
ecological studies when the relations of injurious insects to other
organisms and to external factors were closely investigated.

About the beginning of this century the San Jose scale and the
cotton boll-weevil threatened two important industries, and as a result
of the investigations many advances were made in the use of spraying
machinery and insecticides, notably lime-sulphur wash and hydrocyanic
acid gas, and in the application of biological processes and principles.

In the attempt to solve the problem of the control of the gypsy and
brown-tail moths during the last twelve years another very important
advance was made toward a better understanding of parasitic insects
and of the part they are likely to play in the control of insects in the
future. Regarding the outlook of fighting insects along this line Dr.
Howard says: "There will be a very considerable development of this

INTRODUCTION Xlll

method of warfare against injurious insects in the future. It should be
termed "the biological method of fighting insects" and, looking at the
problem in a broad way, so far as this country is concerned, when we
consider that more than one-half of our principal crop pests have been
accidentally imported from other countries, there seems no reason why a
systematic study of a very large number of parasitic and predatory
insects native to the countries from which these pests were accidentally
imported should not be made with a view of ultimate importation of
all of them into the United States. In fact, since there exist all over
the world beneficial insects, many of which can undoubtedly be accli-
matized here, and some of which will undoubtedly prove of value to
American agriculture, carefully planned work should be begun looking
to the ultimate increase of our insect population by the addition of as
many of these beneficial forms as possible. Of course this would mean
a very great amount of careful biological study in the countries of origin
by men specially trained in this sort of work, if results of value are to be
obtained. Strikingly beneficial results could not be expected speedily,
and, in fact, we might not be able for many years to estimate the bene-
fits derived from such a service; but it seems clear that we should have
in this country as many of these surely beneficial forms as can be
acclimatized."

The greatest impetus to the development of economic entomology
was perhaps the establishment of Experiment Stations and Agricultural
Colleges where courses of instruction were given in this branch of
zoology, and where hundreds of students have been trained to undertake
investigations of the many insect problems that were awaiting solution.
An interesting feature of the latest development in the study of inju-
rious insects is the method of investigation that has been adopted in
most entomological stations. "Field stations" where the insects are
studied under both field and laboratory conditions are established in
infested areas, each in charge of an expert and a staff of assistants.
These officers also keep in close touch with the insect conditions of the
district, and are often able to "test out" control measures at many
places by interesting the farmers and orchardists in the valuable work
they are conducting.

Even in a sketch of the main features of the rise of American eco-
nomic entomology, such as this is, mention must be made of some of
the pioneer entomologists who laid firmly and well the foundations of

XIV INTRODUCTION

this modern science. Dr. T. W. Harris (i 759-1856) in Massachusetts,
Dr. Asa Fitch (1809-1879) in New York, Townend Glover at Washing-
ton, B. D. Walsh (1808-1869), Dr. C. V. Riley (1843-1895) in Missouri
and at Washington, Dr. W. Le Baron and Cyrus Thomas in Illinois,

and Dr. W. Saunders (1835-1914), Dr. C. J. S. Bethune (1838 ) and

Dr. James Fletcher (1852-1908) in Canada stand out prominently on
account of the excellent investigations of the life-histories of injurious
insects and their careful determination of effective methods of control.
{See frontispiece.)

ECONOMIC ENTOMOLOGY
PART I

THE STRUCTURE, GROWTH AND ECONOMICS OF
INSECTS

BRANCH ARTHROPODA (Arthropods)

Crabs, crayfish and lobsters, spiders and scorpions, centipedes and
millipeds have in common with insects jointed appendages and seg-
mented, bilaterally symmetrical bodies with a chitinized external skeleton
(exo-skeleton) — distinguishing characteristics of the great branch
Arthropoda of the Invertebrate animals. These near relatives of
insects may be grouped into four classes:

1. Crustacea. — Aquatic, gill-breathing, wingless Arthropods with
two pairs of antennae and at least five pairs of legs. Examples: Crabs,
crayfish, lobsters, shrimps, sow-bugs, etc.

2. Arachnida. — Air-breathing, wingless Arthropods without anten-
nae, and usually with four pairs of legs. Examples: Spiders, mites,
ticks, and scorpions.

3. Diplopoda. — Air-breathing, wingless Arthropods with one pair
of antennae and numerous body segments each of which bears two
pairs of legs. The mouth-parts consist of a pair of mandibles and a
compound plate. Example: Millipeds.

4. Chilopoda. — Air-breathing, wingless Arthropods with one pair
of antennae and numerous body segments each bearing one pair of
legs. The mouth-parts consist of one pair of mandibles and two pairs
of maxiUas. Example: Centipedes.

(Classes 3 and 4 are frequently grouped as sub-classes of the class
Myriapoda.)

2 ECONOMIC ENTOMOLOGY

Class Insecta (Insects)

The Hexapoda or Insecta are air-breathing Arthropoda with one
pair of antennae, three pairs of legs, and usually one or two pairs of
wings in the adult state.

Insects form a well-defined class of animals, remarkable for the
large number of species. The abundance of some species is so great
that frequently they constitute a menace to the life of plants upon which
they feed. The economic importance of insects is being rapidly realized
by the public in recent years on account of the prominence given to
the part taken by the common house fly in the spread of typhoid
fevers and other diseases, the mosquitoes in malaria and yellow fever,
the San Jose scale and codling worm in orchards, the boll-weevil
in cotton fields, the army worm and hessian fly in grain fields, the
tent caterpillar and bark beetles in orchards and forests, and many
other pests that are causing much annoyance, danger and loss.

The Structure of Insects

EXTERNAL ANATOMY

The body of the insect is bilaterally symmetrical and is divided
into three distinct parts — the head, the thorax and the abdomen, each
composed of a number of segments separated by membranous portions
(Fig. i). Each segment again is made up of a number of sclerites,
hardened plates separated from each other by seams or impressed lines
known as sutures. The skeleton is external, and is in form a hollow
cylinder with the muscles attached within. The skin layer or cuticle
is laminated, consisting of two layers secreted by the underlying
hypodermal cells. The hard tough texture of the skin is due to chitin,
an organic substance resembling that which gives the characteristic
texture to horns and hoofs.

(a) Head. — The skeleton of the head or skull is composed of six
or seven closely united segments, and carries the eyes and antennce.
The mouth is situated on the front ventral surface. The following
regions can be easily recognized:

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

Epicranium

(a) Vertex or crown, the summit of the head, often

with ocelh.

(b) Front or face.

(c) Genae or cheeks.

(d) Occiput, which surrounds the posterior opening of
the skull.

(e) Clypeus, to which the labrum or upper lip is attached,
(/) Gula, to which the labium or lower lip is attached

(see Figs. 2 and 3).

ForeiV/ng ,v Mmdmn<

Fig. I. — Diagram showing the position and arrangement of the principal organs
and appendages of an insect. Ant., Antenna; Br., brain; Ao., aorta; LM., leg mus-
cles originating in the thorax; DM., dorsal longitudinal muscles of abdomen; H.,
heart; MT., Malpighian tubules; ED., efferent duct (oviduct or vas deferens) of
reproductive system; G., gonad (ovary or testis); Cer., cercus; A., anus; Gon.,
gonapophyses; CD., common duct (vagina or seminal vesicle) of reproductive sys-
tem; VG., ganglia of ventral nerve chain; Tr., tracheal trunk showing origin and
distribution of ventral, dorsal and visceral tracheal branches; VM., ventral longi-
tudinal muscles; TS., tergo-sternal muscles; Cox., coxa; Tro., trochanter; Fetn.,
femur; Tib., tibia; Tar., tarsus; SGL, salivary gland; SD., salivary duct; SG., sub-
cesophageal ganglion; Ph., pharynx; S., stomodfEum or fore intestine; M., mesen-
teron or mid intestine; P., proctodaeum or hind intestine.

In addition there is in the head an internal chitinous skeleton
called the tentorium, which acts as a supporting structure. It varies
in form in different insects. but consists essentially of a central plate
and two pairs of arms connecting with the skull. (The tentorium
may be isolated by boiling the head in a 5 per cent, solution of caustic
potash for ten minutes.)

Mouth-parts. — In general there are three types of mouth-parts:
mandibulate, present in the generalized orders and in the Orthoptera,

ECONOMIC ENTOMOLOGY

Pig.

Fig. 3.
a.. Antenna;

E

Fig. 2. — Cephalic view of the head of cricket, a.. Antenna; e., compound eye;

epicranium; 6.1. , lateral ocellus; o.m., median ocellus; e.s., sutures of the epi-
cranium; C, gena; Cp., C.a., clypeus; L., labrum; Md., mandible; p.m., maxillary
palpus; p.l., labial palpus.

Fig. 3. — Caudal view of head of cricket. E., Epicranium; 0., occiput; P.P.,
occipital foramen; P.G., postgena; SM., submentum; M., mentum; gl., glossa; pgl.,
paraglossa; pg., palpiger; pi., labial palpus; C.i, C.2., cardo, pf., palpifer; g., galea;
s., stipes; I., lacinia; p.m., maxillary palpus; md., mandible.

Fig. 4. — Labrum and clypeus of cricket.

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

Ephemerida, and Coleoptera; suctorial, present in the Hemiptera,
Lepidoptera and Diptera; and mandihulate-suctorial in the Hymen-
optera. The mouth-parts with the exception of the labrum are true
appendages of the head segments, and in the embryo arise in exactly
the same way as the legs and antennas.

Mandibulaie Mouth-parts. — The mouth-parts of biting insects
consist of: the labrum or upper lip attached to the clypeus (Figs.
2 and 4) ; a pair of mandibles, simple and unjointed, articulated to the
gencB; a pair of maxillcB, each made up of a basal one-, or two-jointed

p.m.

Fig. 5. Fig. 6.

Fig. 5. — Mandible of cricket. A, Cephalic view; B, caudal view; mh., mem-
brane; mc.i, mc.2, adt., adductor muscles; abt., abductor muscles.

Fig. 6. — Maxilla of cricket. C.i, C.2, Cardo; Mb.2, base of maxilla; pf., pal-
pifer; st., stipes; p.m., maxillary palpus; g., galea; /., lacinia.

hinge segment, the cardo, a central segment the stipes which bears the
palpifer to which the typically five-jointed palpus is attached, and two
distal lobes the outer of which is termed the galea and the inner the
lacinia (Fig. 6). The labium or lower lip, composed of a broad basal
part, the submenfum, joined to the gula, a mentum or central portion,
a pair of jointed palpi attached to the mentum by means of a small
sclerite, the palpiger, and a median part which may be simple or
slightly bilobed in which case it is termed the ligula, or it may consist

ECONOMIC ENTOMOLOGY

of a distinct pair of inner and outer lobes termed respectively the
glosscB and paraglosscB (Figs. 3 and 7). A comparison of Figs. 6 and 7
will show a perfect homology between the segments of the maxillae
and of the labium. The hypopharynx or tongue united to the base
of the labium; and the epipharynx under the labrum and clypeus
bearing teeth, tubercles or bristles (Figs. 8 and 9).
These parts diflfer greatly in the different orders.
Suctorial Mouth-parts. — The suctorial mouth-parts of flies, bugs,
moths and other insects have been evolved from the primitive mandibu-
late type. In some forms such as the squash bug and mosquito all
of the mouth-parts are present and it is comparatively easy to identify

them with the corresponding append-
ages of the biting insects. In other
forms, however, the house-fly for ex-
T^^^^PSrf ample, some of the mouth-parts are
missing or fused with others, and it is

Fig. 7. Fig. 8.

Fig. 7. — Labium of cricket, hyp., Hypopharynx; gl., glossa;
pi., labial palpus; pg., palpiger; m., mentum; sm., submentum.
Pig. 8. — The labrum-epipharynx of cricket.

I., paraglossa;

more difficult to determine their homology. The following descrip-
tions will illustrate the typical arrangements in the three chief purely
suctorial orders of insects. Three types occur in the Diptera — the
piercing type, with all the mouth-parts present, e.g., the female horse
fly and mosquito; the piercing type with some of the mouth-parts
missing or fused, e.g., the horn flies and stable flies, and the non-
piercing type such as the house-fly and blow flies in which the beak
is used for rasping and sucking.

Mouth-parts of the Horse Fly (Tabanid). — The mouth-parts of the
female are composed of six blades loosely ensheathed in the labium

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 7

which is the conspicuous median portion terminating in a large labellum
(Fig. id). The mandibles are flat and sword-Hke; the maxillae are
narrower, but with broad conspicuous palpi; the hypo pharynx and
labrum-epipharynx are also narrow and lancet-like.

ad.md.

depJb.

Pig. 9. — Front of head of Gryllus pennsylvanictis with face and vertex removed.

Upper Figure. — Epic, Epicranium; Ad., prd.. Id., dilator muscles of the pharynx;
Md., mandible; Ph., pharynx.

Lower Figure. — Longitudinal dorsoventral section through the head of Gryllus
pennsylvanictis. prd., prd. 2, prd.3, pstd., Vd., Dilators of the pharynx; Oc, ocellus;
Ad.md., adductor of the mandible; Dep.hyp., depressor of the hypopharynx; Hyp.,
hypopharynx; r.hyp., retractor of the hypopharynx; ap.lb., apodeme of the labium;
r.hyp., retractor of the hypopharynx; Jl.st., flexor of the stipes; T.C., central plate
of the tentorium.

Mouth-parts oj Mosquito. — The mouth-parts are similar in number
to those of the horse fly but they are more bristle-like (Fig. 11).

Mouth-parts of the House-fly. —When the head of a living house-fly is
pinched between the thumb and finger the mouth-parts are protruded
to their full length. They constitute a soft "proboscis" enlarged at

8

ECONOMIC ENTOMOLOGY

the tip into a pair of soft cushion-like lobes, the oral lobes or lobelia
(Fig. 12). The under sides of these lobes are traversed by a large
number of open channels, the pseudo-trachece, which open into the mouth
situated near the middle; the greater portion of this proboscis is the
modified labium. Lying above the grooved labium is the small spade-
like labrum which may be raised by a pin. Near the base of the probos-
cis and above the labrum are two small lobes, the maxillary palpi, the
maxillae being fused with the fleshy base of the labium.

Fig. 10. — Head and mouth-parts of a horse-fly (Tabanus). The maximum
number of parts is retained, but the piercing structures are distinctly blade-hke.
Dipteron type, second subtype. A, Side view of head showing: i, antenna (brachy-
cerous); 2, compound eye; 3, labium; 4, labella; 5, maxillary palpus; B, piercing
structures exposed, labium removed; 6, mandibles; 7, maxillae; 8, hypopharynx; 9,
labrum-epipharynx. {After Herms.)

Mouth-parts of the Stable Fly. — The proboscis is awl-shaped and is
adapted for both piercing and sucking (Fig. 13). It projects forward
horizontally and has a prominent elbow. The labella are small and
are provided with cutting and adhesive structures. Lying above and
within the folds of the proboscis or labium are two unequal, sharp heavy
bristles, the larger representing the labrum and the smaller the hypo-
pharynx. The maxillary palpi are not so large as those of the house-
fly. The palpi of the Horn Fly are longer and more flattened, and
the proboscis is plumper and not thrown so far forward.

Mouth-parts of the Squash Bug. — -The mandibles and maxillae are
reduced to needle-like structures, the two innermost (the maxillae) are
united to form a piercing tube. The needles fit in the groove of the

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 9

jointed beak, the modified labium. The labrum closes the base of the
groove (Fig. 14).

I li h

Fig. II. — Mouth-parts of female mosquito (Culex pipiens). A, Dorsal aspect;
B, transverse section; C, extremity of maxilla; D, extremity of labrum-epi-
pharynx; a., antenna; e., compound eye; h., hypopharynx; I., labrum-epipharynx;
li., labium; m., mandible; mx., maxilla; p-, maxillary palpus. {After Folsom and
Dimmock.)

Fig. 12. — Mouth-parts of the house-fly (Musca domestica). lb., Labrum; tnx.p.,
maxillary palpi; li., labium; la., labellum. {After Kellogg.)

Mouth-parts of the Butterfly. — The long sucking tube is composed of
the two maxillae joined together, while the other mouth-parts are
rudimentary (Fig. 15).

lO

ECONOMIC ENTOMOLOGY

Mandibulate-siidorial Mouth-parts. — Among the Hymenoptera we
find a combination of the two types — well-developed biting mandibles
and a labium or hypopharynx fitted for sucking or lapping liquid food.
In ants and sawflies the mandibles are more in evidence, while the bees
and wasps have well-developed sucking apparatus. Ants use their
mandibles for various purposes, including the comminution of food,
building of nests, transportation of larvae, slaves, etc., and in attack and
defence against their enemies; the hypopharynx is used in lapping Hquid
food.

Selat

Lahruin

Jhealh, = labium
Jetae,- Mandible and AloxiUot,

Fig. 13. Fig. 14.

Fig. 13. — Side view of the head and mouth-parts of the stable fly {Stomoxys calci-
trans). Stylets reduced in number and closely ensheathed by the labium, i.
Antenna; 2, compound eye; 3, labium; 4, labella; 5, labrum; 6, hypopharynx; 7,
maxillary palpi. {After Herms.)

Fig. 14. — Beak of a hemipteron. {After Riley and Johannsen.)

Mouth-parts of the Honey Bee. — These consist of the labrum and
epipharynx above with the short trowel-like mandibles on each side for
moulding wax; the maxilla forming conspicuous lateral wings with the
galea and lacinia fused into one piece, and the palpi minute (Fig. 16).
The labium is the long portion on each side of the tongue and ends in a
pair of palpi. The middle tongue is the hypopharynx ending in a small
labellum.

Antennae. — ^The antennae or feelers are sensory organs, and are very
variable in structure. They carry the organs of touch, and probably
those of smell and hearing in some cases. On the surface of some of the

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

II

segments are fine hairs, connected below with nucleated nerve cells,
which are believed to be tactile hairs. There are too in some cases pits
or oval depressions, also connected with a nerve cell, which are thought
to be gustatory organs. Other pits situated in patches at the lower end
of the segments are beheved to be auditory organs.

Eyes. — The eyes of insects are of three kinds: simple, compound and
agglomerate. The simple eyes or ocelli appear externally as a single
convex lens, and are borne by the most primitive insects such as the
Collembola, all eyed larvae, and in the
adults of most of the winged insects. In
winged forms there are usually three, supple-
mentary to the compound eyes, and borne
on the vertex or on the front, arranged
generally in a triangle. The agglomerate
eye is a compound eye in which the facets
are not fused but well separated from each
other, e.g., male Coccids.

Organs of Hearing.- — Several kinds of
auditory organs occur in insects and these
are variously located. In locusts they are
tympanic membranes, located on the base
of the abdomen; in the katydids and
crickets on the tibiae of the fore legs. In
the mosquitoes and many other groups
certain sensitive hairs on the antennae serve
to take up and transmit sound waves.

Organs of Smell.— These organs are butterfly (Vanessa), a.,

° ^ , tennse; /., labial palpi; p.,

variously located — on the antennae in flesh boscis. (After Foisom.)
flies, ants, bees and wasps, some moths and

beetles; on the maxillary and labial palpi in Perla and Silpha; and
on the cerci in the cockroach and some Orthoptera.

Organs of Taste. — Taste organs are also variously located — on
the hypopharynx in the honey bee, on the epipharynx of most biting
insects, and on the maxillary palpi in wasps.

All sense organs consist essentially of the following parts: (i) a
nerve of the central nervous system communicating with (2) one or
two modified hypodermal cells, and (3) external supporting or accessory
structures such as setce, tubercles or pits.

Fig. I 5

-Head

of a
An-
pro-

12

ECONOMIC ENTOMOLOGY

Fig. i6. — Head and mouth-parts of the honey bee {Apis melliferd). Both types
of mouth-parts well developeti but the mandibles are used chiefly for portage and
modeling (Hymenopteron type). A, Front view of the head showing: i, antennae;
2, compound eyes; 3, simple eye; 4, labrum; 5, mandibles; 6, maxillae (lacinia); 7,
labium (palpi only); 8, hypopharynx(?); B, mouth-parts removed to show the
parts; 5, mandibles; 6, maxillae (lacinia); 7, labium (palpi only); 8, hypopharynx
(?); 9, bouton; lo, maxillary palpus; 11, mentum; 12, submentum; 13, cardo; 14,
stipes. {After Hertns.)

Fig. 17. — Section through the thorax of an insect. L., Leg; P., pleuron; S., sternum;

T., tergum; W., wing.

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

13

Special Organs of Sense. — The halteres of Diptera contain sensory
organs, but their function has not yet been definitely ascertained.

pron.

Fig. 18. — Gryllus pennsylvanicus. A, Ventral view of thorax; B, dorsal view of
thorax, distal portion of pronotum removed; C, lateral view of thorax and abdomen.
Cox., C0X.2, Cox-z, First, second and third coxae; Stl., prosternellum; 5/. 2, 5/. 3,
meso- and meta-sternum; Pron., pronotum; £0.2, £5.3, meso- and meta-episternum;
Em.2, Em.T,, meso- and meta-epimeron; i, 2, 3, etc., abdominal tergites; 1', 2', 3',
etc., abdominal sternites; p., peritreme; S., spiracle; sp., supra anal plate; C, cercus;
Ovp., ovipositor; pi., pleuron; Sc.2, Sc.3, meso- and meta-scutum; Scl.2, Scl.3,
meso- and meta-scutellum; p.scl., postscutellum; W., W.2, wing bases.

When deprived of halteres flies cannot maintain their equilibrium in the
air.

14

ECONOMIC ENTOMOLOGY

■tr

f

tb

(b) Thorax. — The thorax is composed of three segments — the
pro-, meso-, and meiaihorax, each having a pair of legs. The meso-
thorax and metathorax bear wings. Each segment is divided into a
dorsal part, the notum or tergum, a ventral part, the sternum, and
two laterals, the pleura (Fig. 17). Each part is again divided by
sutures into sclerites — the notum into prcescutum,
scutum, scutellum and post-scutellum, and the pleuron
into episternum and cpimeron (Fig. 18).

In most hymenopterous insects the first abdom-
inal segment — the propodeum or median segment
— is fused with the thoracic mass, so that the petiole
of such insects is not the first but the second abdom-
inal segment.

Legs. — Each leg is composed of the following
parts: coxa, trochanter, femur, tibia, and tarsus (Fig.
19). The trochanter in certain Hyraenoptera is
made of two segments, while the tarsus in most in-
sects is composed of several segments, the last bear-
ing a pair of claws. In some insects, e.g., the Diptera,
three appendages are borne between the claws, in
which case the outer pair are termed pulvilli and the
middle one the empodium.

Wings. — The two pairs of wings are attached to
the meso- and the metathorax. They are membran-
ous expansions of the body wall with hollow thick-
enings along certain lines called veins or nerves.
These veins often branch and interlace, and the spaces
between the veins are called cells. Much import-
ance is attached in classification to the wing and its
veins on account of the great variation not only in
the orders and families but even in the genera of a
family.

Structurally the wings of insects may be grouped

into three divisions:

I. Where the fore and hind wings are of similar texture and more or

less fan-like. Under this division fall the Dragon flies, in which both the

size and form of the wings are very much alike. Butterflies, wasps, and

bees have their hind wings smaller than the fore wings, while some of the

Fig. 19. — Leg
of a beetle {Calo-
ioma caliduni).
c, Coxa; c/., claws;
/., femur; i., spur;
t.^-t.'^, tarsal seg-
ments; tb., tibia;
tr., trochanter.
{After Folsotn.)

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

15

May flies and the males of scale insects have their hind wings very
much reduced or entirely wanting. In the flies (Diptera) the hind
wings are converted into halteres (balancers).

2. Where the fore wings are either wholly or partially chitinized.
Examples of such thickening of the wings occur among the grass-
hoppers and crickets, the beetles
and the heteropterous bugs.

3. Where the hind and fore
wings are strongly reduced or
completely atrophied, as in the
fleas (Siphonaptera), bird-lice
{Mallophaga) and sucking lice
{Siphnnculata) .

Venation. — It has been found
that the system of veins in the
different orders of insects is
fundamentally alike, being de-
rived from the primitive type
fairly well seen in some stone-
flies and some cockroaches.
This fact becomes evident only
when a comparison is made of
the wings of the more general-
ized members of the different
orders, as specialization has
greatly modified their structure
in most genera. Comstock and
Needham have shown by a
study of the developing wings

of nymphs and pupaj that the /'^- 20.--Several stages in the de-
"^ , .... . . velopment of the wings of a cabbage butter-

principal longitudinal vems m fly. {After Met cer.)

the more generahzed orders are

formed about tracheae (Fig. 20). In the development of the wing
these tracheae grow out into the wing-bud, and later the veins are
formed about them. The cross veins, however, as a rule do not arise
in this manner, as tracheae are apparently absent. In the course of
development specialization has brought about changes in the venation,
recognized, first, by the addition of veins through branching of the prin-

i6

ECONOMIC ENTOMOLOGY

cipal veins as in many Neuropteroids and Orthopteroids; second, by the
addition of cross veins; and third, by the reduction of the number of veins

§£L Sc2

3dA 2dA

IstA

Fig. 21.

-The hypothetical primitive type of wing venation.
Needhatn.)

{After Comslock and

through coalescence of adjacent veins, or by the disappearance of veins,
as in most moths, flies and hymenopters. The chief longitudinal veins

are the costa (C), an unbranched vein on
or near the front margin; the suhcosta
(Sc); the radius (R); the media (M); the
cubitus (Cu); and the anal veins (A),
typically three but often reduced to one
or two.

A knowledge of the different types of
venation is very important in classifica-
tion. The Comstock-Needham system of
terminology is adopted in this Classbook,
and students should consult the recent
work of Professor Comstock — The Wings
of Insects — for a full discussion of the
general characteristics of the wings of the
several orders of insects.

Clothing of the Wings. — While the wings
of many insects are naked, many are
covered with fine setae, hairs, or scales.
The coating of scales is the most distinc-
tive feature of the wings of the Lepidop-
tera. These scales are modified setae,
being evaginations of greatly enlarged
hypodermal cells. They are provided
with ridges, these serving to increase their rigidity and their protec-

FiG. 22. — Various forms of
scales. A, E, Thysanuran
{Machilis); B, beetle {Anthre-
nus); C, butterfly (Pieris); D,
moth (Limacodes) .

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 1 7

tive value (Fig. 22). In addition, the beautiful colors are due to
the scales, and are produced (i) by the pigments present, (2) by the
reflection, refraction or diffraction of light, or (3) by a combination
of these causes. Scent glands, called aiidroconia, are associated with
the scales, mainly on the wings of males.

(c) Abdomen. — The abdominal segments show a greater uniformity
in form than do the thoracic segments, owing to the fact that the former
are not speciahzed for the bearing of legs and wings. This uniformity
is not merely external but extends to some of the internal organs,
notably the muscular, respiratory and nervous systems. A greater
differentiation and consequent difference from the other segments is
usually found in the terminal segments which are modified to bear the
genitalia and cerci, in the first segment in the Hymenoptera which has
united closely with the thoracic mass, and in the petiole of the same
insects which is greatly reduced in diameter and often nodulated (ants).

Typically the abdomen consists of ten segments, but in some
Orthoptera eleven have been found and twelve in a few embryos. In the
adult insect it is often difficult to distinguish ten abdominal segments
owing to the fusion or disappearance of certain of the segments, to the
modification which the terminal segments undergo, or to the telescoping
of these last within the other segments. Each segment is made up of a
dorsal Sclerite, the tergum, a ventral sclerite, the sternum, and a pair of
pleural membranes connecting the two. The first seven or eight
abdominal segments usually bear a pair of spiracles each. Typically
the anus opens in the tenth or last segment and the reproductive system
between the eighth and ninth.

Appendages of the Abdomen. — In the embryo the abdominal seg-
ments bear paired appendages which are homodynamous with the legs
and mouth-parts. These usually for the most part disappear on hatch-
ing, but they persist as prolegs during the larval Ufe of the Lepid-
optera, Tenthredinidae and Mecoptera; in certain Thysanurans they
persist as rudimentary abdominal appendages throughout the life of
the insect.

The cerci which are present in most of the more generalized orders
and in the thysanuriform larvae are usually the appendages of the tenth
abdominal segment.

The gonapophyses or plates of the genitalia are the appendages of
the seventh, eighth and ninth segments and are known respectively as

1 8 ECONOMIC ENTOMOLOGY

the ventral, inner and dorsal plates. The inner pair usually forms the
ovipositor or the intromittent organ, and the outer pairs may form a
sheath or claspers.

The Genitalia. — A knowledge of the genitalia is of importance to
the taxonomist because in certain families the separation of species
is based largely on these structures. It is also of importance to the
economic entomologist because it enables him to understand the
method of egg deposition in injurious and beneficial insects and
the poisonous action in certain forms in which the ovipositor has been
modified to form a sting.

Fig. 23. — Abdomen of female house-fly, showing extended ovipositor, a., Anus; c,
cercus; d.p., dorsal plates; v. p., ventral plate.

There is no true ovipositor in the Neuropteroida, Coleoptera,
Lepidoptera or Diptera, the vagina opening directly to the exterior
(Fig. 23). In some of these insects, however, a whip-Hke or tubular
pseudo-ovipositor is formed by the last few segments of the abdomen
{e.g.y Cerambyx, Cecidomyia, Musca).

A true ovipositor is developed in the Thysanura, Orthopteroida,
Hemiptera and Hymenbptera (Fig. 24). In the Orthoptera the gona-
pophyses are used for making holes in the ground or shts in stems for
the reception of the eggs. In the Hymenoptera there are various
peculiar modifications of the ovipositor: Megarhyssa, one of the larger
ichneumon flies, uses its long ovipositor as a drill, forcing it, in spite
of its extreme slenderness, up to the hilt in the trunk of hardwood
trees in order to deposit its eggs in the burrows of the horn-tail borer

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

19

{Tremex columba); the saw flies have the inner plates united to form
the egg channel, the upper plates form a sheath, while the lower have
serrate edges and are wielded Hke a saw, making slits in leaf or stem
for the deposition of the eggs. In the stinging hymenoptera the
ovipositor is modified to form a sting; the upper valves of the honey
bee are soft, forming a pair of palpi, the inner lobes form a sheath,
and the ventral lobes are represented by a pair of barbed darts. The
poison is of two kinds, one alkaline the other
acid, and is secreted by glands within the
abdomen.

INTERNAL ANATOMY

The internal anatomy of an insect may
be discussed under the following heads: {a)
muscular system; {b) respiratory system;
(f) circulatory system; {d) intestinal or
digestive system; {e) nervous system; (/)
reproductive system (Fig. 25).

(a) Muscular System. — The muscular
system xif insects is well developed. The
muscles are attached to the inner surfaces
of the exoskeleton.

In the abdomen the arrangement of
th.e muscles is the same in each segment,
except at the extremity where special mus- apparatus of honey bee. ag.,

^ . . -^ ^ . Accessory gland; p., palpus;

Cles exist for moving the ovipositor, the pg., poison gland; r.. reser-

cerci or other terminal organs. In the ^ J^ ;'" ^^"'^- ^'^^^''' ^"'''
sternum of each abdominal segment there

are one or two sets of longitudinal muscles on each side of the nerve
chain. These are the longitudinal sternals or ventral recti (Fig. 26). In
the tergum also similar sets of muscles occur on each side of the dorsal
vessel; these are the longitudinal tergals or dorsal recti. Between these
longitudinal muscles and the integument are numerous oW/g«e and trans-
verse muscles, and these, with the longitudinal muscles, bring about the
various turning, wriggling or telescoping movements of the abdomen.
In each abdominal segment there are also two muscles which pass
from the tergum to the sternum. These are the tergo-sternals which

Fig. 24. — Sting and poison

20

ECONOMIC ENTOMOLOGY

bring about the contraction and expansion of the abdomen necessary
for respiration.

In the thorax of larval insects and of the wingless forms the arrange-
ment of muscles follows the same general plan as in the abdomen,
but the presence of the leg muscles makes it more complicated (Fig.
27). In the winged insects, however, this primitive arrangement
cannot be readily recognized owing to the presence of large wing muscles
and also to the fact that the thoracic segments are very often fused
together. The muscles which move the head originate in the prothorax
and are inserted into the base of the head. Within the head are muscles

Fig. 25. — Internal organs of the cricket {Gryllus pennsylvanicus). AN., Anten-
nal nerve; Oes., oesophagus; Br., brain; T., teutorium; Ao., aorta; S., suspensorium
of ovary; H., heart; Ov., right ovary; Col., colon; R., rectum; A., anus; MT., Mal-
pighian tubules; Od., oviduct; Op., ovipositor; BC, bursa copulatrix (copulatory
pouch); Vag., vagina; RS., receptaculum seminalis; Mes., mesenteron; VC, con-
nectives of ventral nerve chain; VG., ganglia of ventral nerve chain; S.GL, salivary
glands; Lb.N., labial nerve; SG., subcesophageal ganglion; Md.N., mandibular nerve;
SD., salivary duct; HP., hypopharynx; P., pharynx; Mx.N., maxillary nerve; LN.,
labial nerve; ON., optic nerve; C, crop; P., proventriculus; GC., gastric cseca.

for the control of the mouth-parts and antennae. In the mandibulate
insects the muscles which move the mandibles occupy the greater
part of the head cavity.

Mention should also be made of the alary muscles of the heart,
the circular and longitudinal muscles of the digestive canal, and the
spiracular muscles which bring about the closure of the spiracles during
respiration.

A muscle consists of a bundle of long fibres, each with several nuclei
and a sheath, the sarcolemma. In most cases the fibres present a
striated appearance due to the presence of alternate light and dark
bands.

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 21

el.

tridt..

v.rma/.

vrmin.

Fig. 26. — Ventral surface of larva of Sphida obliqua, showing arrangement of
parts. AN., Antennal nerve; CL., clypeo-labral nerve; Al.c, alimentary canal-
LG., lateral ganglion; /;-., tracheal trunk; tr.lat., tergo-sternal muscles; v.r.maj',
v.r.min., ventral longitudinal muscles; S.lig., suspensorium of testes; Test., testis-
V.d., vas deferens; Sp., spiracle; T., thoracic ganglia; /, II, III. etc. abdominal
ganglia; o.l., oj.cr.ing 'nto leg; tr.r., transverse nerve; BB., brain.

2 2 ECONOMIC ENTOMOLOGY

(b) Respiratory System. — The exchange of gases in respiration
is effected by means of a system of small tubes called trachea which
extend inward from the surface and branch to all parts of the body.
The external openings, called spiracles, are situated on the sides of the
thoracic and abdominal segments (Fig. 28). From each spiracle
a short tube runs inward and connects with the trunk tube running
along the side of the body. There are thus two main or trunk tracheal
tubes, one on each side of the body. Each gives off three large branches
to each segment, the upper, the middle, and the lower. Each of these

vf/.f.

Ext Tib,

Fl.T/b. TlTjUFiTars
Ext.Tarij

Fig. 27. — Muscles of hind leg of Gryllus pennsylvanicus. Ext.F., Extensor of
femur; Ext.Tib., extensor of tibia; Exl.Tar.i, extensor of first tarsal joint; Ext.Tar.2,
extensor of second tarsal joint; Exl.Tar.3, extensor of third tarsal joint; Fl.Tat.i,
flexor of first tarsal joint; Fl.Tar.2, flexor of third tarsal joint; PLC, flexor of claws;
Ext.C, extensor of claws; Fl.F., flexor of femur; Fl.Tib., flexor of tibia.

branches subdivides frequently so that every portion of the segment
is entered. Moreover, these fine tubes anastomose to form a deli-
cate network, and allow a continuous circulation of air to take place.

In many insects, in addition, are large sac-like dilatations of the
tracheae which serve as air reservoirs.

Tracheae have a striated appearance due to the thickening of the
chitinous wall into a compact elastic spiral, thus preventing the collapse
of the tubes. Special respiratory devices are seen in aquatic insects.
Nymphs of May-flies and Damsel-flies have lamellate tracheal-gills,

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

nymphs of Stone-flies and Caddice-
flies have filiform or cylindric tra-
cheal-gills, larvas of Culex, Corethra,
Simiilimn and Chironomus have
blood-gills, while nymphs of Dragon
FHes have internal tracheal-gills .
Tracheal gills are outgrowths of the
body wall with fine tracheal tubes,
in which there occurs during res-
piration an exchange of gases be-
tween the air in the tubes and the
water. They are usually external
but in the nymphs of Dragon Flies
they are internal, being arranged
in rows on the inner walls of a gill
chamber in the posterior portion
of the alimentary canal.

Blood-gills are outgrowths of the
body wall in which the blood flows.
The exchange of gases in respira-
tion occurs between the blood in-
side and the water outside.

Structurally a trachea consists
of a chitinous wall or intima as a
lining membrane spirally thickened
at regular intervals by elastic
threads called tcBnidia, and a cellu-
lar wall of hypodermal cells, the
pavement epithelium .

(c) Circulatory System. — While
there is a blood circulation in insects
the only blood vessel is a dorsal
tube lying just beneath the notum.
The heart or posterior portion of
the dorsal tube contains a number

Fig. 28. — Respiratory system of the
larva of the budmoth (Tmetocera ocel-
lana) . (Insect opened along the median
of ventricles or chambers, each with dorsal line.) C, tracheal commissure;

a lateral valve which allows the ^- ^°"'^^ ^'■^"'=^= ^- supplying heart;

blood to flow in but not out. There

v., ventral branch; F5., visceral branch.

24

ECONOMIC ENTOMOLOGY

are also valves between the chambers so that when the latter con-
tract the blood is forced forward. The blood on leaving the ventri-
cles passes into the aortic portion of the dorsal tube, toward the head,
and thence flows into the body cavity bathing all the organs. The
blood is usually colorless and consists of two portions — the watery
serum and the white blood corpuscles.

Fat-bodies. — These are masses of fat-cells occupying a large part of
the cavity of the body, and lying between the organs. At first the fat-
cells are large and spherical, but they lose their structure to a large
extent through breaking down. They contain nourishing albuminoid
matter, besides uric acid and urates. Their exact function is not

Fig. 28a. — Apparatus for closing the spiracular tracheae in a beetle (Lucanus).
A, Trachea opened; B, closed; b., bow; bd., band; c, external cuticula; I., lever; m.,
muscle; s., spiracle; /., trachea. {After Judeich and Nitsche.)

definitely known. Associated with the fat-bodies in the abdomen of
larvae are large yellow cells called cenocytes which, according to Glaser,
secrete an oxidizing enzyme.

{d) Intestinal or Digestive System. — This system occupies the central
portion of the body, and is divided into distinct regions with special
functions (Fig. 29) . The food passes from the mouth into the pharynx
where it is subjected to the action of saliva secreted by the salivary
glands. Thence it passes in the Orthoptera and Coleoptera through
the oesophagus into the crop, a folded and membranous pouch, where
the action of the sahva is completed. The partially digested food then
passes into the gizzard or proventriculus , a muscular enlargement armed
with teeth for the purpose of straining the contents before entering the
true stomach or ventricuhts, In many caterpillars the food passes

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 25

Fig. 29. — Digestive canal of Gryllus pennsylvaniciis. sd., Salivary duct; Oes.,
oesophagus; Sg., salivary gland; C, crop; pv., pv.", proventriculus; gc, gastric caeca;
m., mesenteron; Mv., valve between two divisions of the mesenteron; gl., digestive
glands; il., ilium; u.d., duct of malpighian tubules; ut., malpighian tubules; Col.,
colon; rt., rectum; An., anus.

26

ECONOMIC ENTOMOLOGY

Fig. 30. — Dorsal view of ali-
mentary canal of the larva of the
budmoth {Tmetocera ocellana).
Ph., Pharynx; Oes., oesophagus;
SM., suspensory muscles; Tr., vis-
ceral tracheal of left side; MT.,
Malpighian tubules; Mes., mesen-
teron; Int., small intestine; In.,
intestinal nerve; R., rectum.

directly into the stomach which is long.
Further digestion occurs here through
the action of secretions of the c(Bcal tubes,
often called the gastric cceca, which con-
sist of glandular pouches emptying into
the anterior end of the stomach. Most
of the digested food is here absorbed
and passes into the circulation. Pos-
terior to the stomach is the intestine
which consists of three parts — ileum,
colon, and rectum. Into the ileum open
the Malpighian tubes which are excretory
in function, similar to the kidneys of
higher animals. The undigested portions
of food are expelled through the rectum
and anus.

Some variations may be noted. The
oesophagus is long in those insects that
suck their food, and short in herbivo-
rous forms. In sucking insects the giz-
zard may be absent, and the crop is often
a side pocket of the oesophagus (Fig. 30).

Structurally, the wall of the alimen-
tary canal consists of:

1. An epithelial layer of cells which
secrete the intima or lining layer.

2. The delicate basement membrane.

3. Circular muscles.

4. Longitudinal muscles, which aid in
constricting and enlarging the canal

(Fig. 31)-

From an embryological point of view
the alimentary tract consists of three
primary regions:

1. The Stomodceum, embracing the
fore part as far as the stomach.

2. The Mesenteron, or mid-intestine
embracing the stomach, and

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

27

Fig. 31. — Sections through the proventriculus of Gryllus pennsylvanicus. (All
greatly enlarged.) i. Longitudinal section through the median denticles. 2.
Transverse section passing through two folds of the anterior division of the proven-
triculus. 3. Surface view of a portion of one of the dental folds showing the chi-
tinous partition and four of the transverse rows of teeth. 4. Transverse section
of proventriculus passing through the median denticles. 5. Transverse section of
fold cut in the region of the lateral denticles. 6. Lateral view of two adjacent inner
barbated lobes, hr., Bristles of anterior division of proventriculus; ch.p., chitinous
partition between dental folds; cm., circular compressing muscles; c.v., cardiac
valve; ep., epithelium; i.bl., inner barbated lobes; in., intima; l.d., lateral denticle;
l.t., lateral tooth; m.d., median denticles; m.t., median tooth; o.b.L, outer barbated
lobes; r.m., relaxing muscle.

28 ECONOMIC ENTOMOLOGY

3. The Proctodeum, embracing the portion posterior to the stomach.
The stomodoeum and proctodoeum are ectodermal in origin while the
mesenteron is probably entodermal.

(e) Nervous System.— The nervous system of insects consists
essentially of a series of ganglia joined by a double nerve-cord lying
along the ventral surface of the body. Each primitive segment had a
double ganglion, but in most insects fusion of ganglia occurs in the head,
the thorax, the anterior and the posterior portions of the abdomen.
Great variations occur even in the same order. The largest ganglion
is in the head, and is the result of the fusion of three pairs. It forms
the brain or supra- (esophageal ganglion, lying above the oesophagus.
There is also another large ganglion, the suh-cesophageal, lying below the
oesophagus, and connected with the brain by a double nerve-cord about
the oesophagus, the oesophageal nerve collar or commissure. It also repre-
sents the fusion of three pairs of ganglia.

From the brain nerves are given off to the antennae, eyes, and
labrum. The sub- oesophageal ganglion controls the mouth-parts.
From the ganglia in the thorax and abdomen nerves supply the various
segments and control their movements and activities (Fig. 26).

In addition there is the Sympathetic nerve system which mainly lies
along the dorsal hne of the alimentary canal. It consists of a recurrent
nerve arising from a, frontal ganglion and ending in a stomachic ganglion.
Two pairs of lateral ganglia are connected with the recurrent nerve and
supply nerves to the dorsal vessel and the tracheae of the head. A
ventral system lies in the main nerve cord and activates the spiracles.

Nerve-cord and Ganglia. — The nerve-cord consists of an axis-cylinder
of fibrillae and a sheath. It is concerned with the transmission of
impulses and stimuli. The ganglion is a centre for the regulation of
nutrition. It consists of a dense cortical layer of gangUonic cells with
large nuclei, a clear medulla from which nerve fibrillae originate, and a
nerve sheath.

(/) Reproductive System. — In all insects the sexes are distinct.
The sexual organs are situated in the abdomen and consist in the
female of a pair of ovaries and a pair of oviducts opening into the vagina
and frequently externally by an ovipositor, and in the male of a
pair of testes and a pair of seminal ducts {vasa deferentia) opening into
the ejaculatory duct and externally by an intromittent organ. The
external opening lies between the eighth and ninth segments of the ab-

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 29

domen— never in the last. In most insects there is in the female a
seminal receptacle, a dorsal pouch of the vagina, and in the male a
seminal vesicle, a dilated portion of the vas deferens. The ova are
formed in the ovarian tubes in different stages of growth, the largest
and oldest being nearest the oviduct. The spermatozoa arise in the

-susp.

-5usp.

ov.

ubr

-~ed.

sp.c.
-int.

Fig. 32. Fig. 33.

Fig. 32. — Male reproductive organs of Gryllus pennsylvanicus. T., Testis; Susp.,
suspensorium of testis; vd., vas deferens; ubr., u.maj., accessory glands on surface
of seminal vesicle; ed., ejaculatory duct; sp.c, spermatophore cup; int., intromittent
organ or penis.

Fig. 33. — Female reproductive organs of Gryllus pennsylvanicus. Susp., Sus-
pensorium of ovaries; O., ovaries; ov., ovarian eggs; od., oviduct; C cercus; r.s.,
seminal receptacle; d., duct of seminal receptacle; vag., vagina; be, copulatory
pouch; Ovp., ovipositor.

follicles of the testes. There are also usually accessory glands which
secrete mucus that envelopes the spermatozoa and ova (Figs. 32 and

33)-

Parthenogenesis, or reproduction without fertilization, occurs in
many insects — in aphids, Cynips, Lasius (Ant), and some Coccids.

30 ECONOMIC ENTOMOLOGY

Several generations of females only which bring forth living young
may occur, but at intervals males appear and fertihzed eggs are laid.

In some species of the Cecidomyiidae the young are produced by
larvae. Such a method is called pcsdo genesis. After several genera-
tions, however, the last larvas pupate and form normal male and female
flies. Examples are Tanytarsus dissimilis and Miastor americana
(Fig. 2>2,a).

Another method of asexual reproduction, called polyembryony
occurs in certain parasitic insects, e.g., Polygnotus, belonging to the
Hymenoptera. Each egg produces many embryos, instead of one,
which develop into as many adult insects of the same sex.

Pig. 33a. — Young pasdogenetic larvae of Miastor in the body of the mother larva.
Greatly enlarged. {After Pagenstecher from Folsom.)

The Development of Insects

All insects that reach maturity pass through two distinct stages
of development — the embryonic changes within the egg, and the
changes after leaving the egg until the adult condition is reached.
The growth of the embryo within the egg progresses from the seg-
mentation of the ovum to the formation of the blastoderm with its
ventral plate and germinal groove, and the gradual growth of the
ectoderm, mesoderm and entoderm, from which layers the various
organs of the body arise.

(a) Embryology. — The egg or ovum is a single cell containing —
(i) The nucleus or germinal vesicle. (2) The yolk, or nutritive material.
(3) The cytoplasm. (4) The cell wall or vitelHne membrane. (5)
The egg shell or chorion. (6) The micropyle or opening in the chorion
to admit the spermatoza (Fig. 34).

When the sperm nucleus unites with the nucleus of the egg, and
forms a segmentation nucleus, fertilization is accomplished.

By division of the segmentation nucleus a large number of nuclei
are formed many migrating outward toward the margin of the egg.
There a layer of cells internal to the yolk membrane called the blasto-

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

31

derm is finally produced. This stage of the embryo is known as the
blastula.

^-Ast.

Pig. 34. — F'ormation of the blastoderm and the germ band. Fk., Cleavage nuclei;
Bl., blastoderm; Kst., germ band. {After Escherich.) ,

The blastoderm thickens by cell division in one region forming
the primitive streak or germ band which presents in surface view an oval
or elongated area along the ventral face of the egg. Soon a groove

Fig. 35. — Diagrammatic sagittal sections to illustrate invagination of germ band
in Calopleryx. a., Anterior pole; ac , amnion cavity; am., amnion; b., blastoderm;
d., dorsal; g., germ band; h., head end of germ band; p., posterior pole; s., serosa; v.,
ventral; y., yolk. {Folsom after Brandt.)

appears in the centre of the germ band due to invagination of the
blastoderm. The lips of the groove close over the invaginated portion,
producing an outer \a.yer, the ectoderm or edoblast and the.inner\a,yer,

32

ECONOMIC ENTOMOLOGY

the endoblast (meso-entoderm) . This stage of the embryo is known as
the gastrula.

Meanwhile the blastoderm is folding over the germ band from
either side, producing an inner membrane — the amnion, and an outer
membrane — the serosa (Fig. 35).

Two types of germ bands may be noted. The overgrown type
retains its original position (Fig. 36), and the blastoderm folds over
the germ band from either side forming the two layers amnion and
serosa. In the invaginated type, seen in aphids and Odonata (Fig. 37),
the germ band invaginates into the egg so that its ventral surface

faces the dorsal surface of the egg.
At a later stage the embryo turns
and regains its original position.

The germ band shows early
signs of segmentation, beginning
first at the anterior end. An in-
vagination of the ectoderm near
the anterior end forms the stomo-
doeum or fore gut, and a similar
posterior invagination forms the
proctodceum or hind gut. The
segmentation shows about 21 seg-
ments, 6-7 to the head, 3 to the
thorax, and 11-12 to the abdo-
men. On each segment except
the first and last a pair of tiny limbs (buds) are seen.

Soon the germ band widens and closes over the yolk to form the
dorsal waU.

Before dorsal closure occurs the beginnings of the nerve-cord
form in the median groove. This primitive nerve-cord is double,
and a pair of swellings in each segment develop into the ganglia of
the ventral system.

The tracheas arise as invaginations of the ectoderm.
The entoderm arises from the endoblast, the inner embryonic layer,
as two cell masses situated at either end of the embryo. These masses
grow backward and forward respectively, and unite to form the mid-
gut {mesenteron) .

The rest of the inner layer forms the mesoderm from which arises

Pig. 36. — Formation of the embryonic
membranes — overgrown type. Am., am-
nion; Ect., ectoderm; Enl., entoderm;
Ser., serosa. {After Korschelt and H eider.)

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

33

the blood system, muscles, reproductive organs, fat-body, etc. The
division of the mesoderm into two layers produces paired cavities in
each segment — the ccelomic pouches (Fig. 37).

{b) Metamorphosis. — The various changes that occur after the
hatching of the egg are comprised under
the term metamorphosis.

After the escape of the embryo from
the egg the development may be (i) holo-
metabolic, i.e., with complete metamorpho-
sis, the insect passing through two distinct
phases, larva and pupa, before assuming
the adult form; (2) heterometaboUc, i.e., with
incomplete metamorphosis, without a dis-
tinct pupal stage, the larva being like the
adult but without wings or mature repro-
ductive organs; (3) ametabolic, i.e., without
metamorphosis, the young being Hke the
adult. Insects belonging to the orders
Neuroptera, Mecoptera, Trichoptera,
Lepidoptera, Coleoptera, Diptera, Sipho-
naptera, and Hymenoptera are holome-
tabolic; the Orthoptera, Platyptera, Ple-
coptera, Odonata, Ephemerida, Thysan-
optera, Homoptera and Hemiptera are
heterometabolic; and the Thysanurans
and Collembolans are ametabohc. Most
insects are oviparous, but some like cer-
tain scale insects and Sarcophagidae are
larviparous.

Larval Stage. — In general two types
of larvae are recognized : the thysanuriform
and the eruciform. The former type is
considered quite generalized and primitive
in form, and is common among the hetero-
metabola. The body is flattened, the legs and antennae are long,
the caudal cerci are well-developed, and the mouth-parts are
mandibulate.

Pig. 37. — Embryo of jEcan-
thus, ventral aspect, a, An-
tenna; a.^-a.^, abdominal ap-
pendages; e., end of abdomen;
I., labrum; li., left fundament
of labium; Ip., labial palpus;
L^-l.^, thoraciclegs; w., mandi-
ble; tnp., maxillary palpus; mx.,
maxilla; p., procephalic lobe;
pr., proctodoeum. {From Fol-
som after Ayers.)

34

ECONOMIC ENTOMOLOGY

The cruciform type prevails among the holometabola. The body
is cyHndrical, and the legs, antennae and cerci are much reduced.

Many transitional forms, however, occur, and it is believed that
the cruciform type has been developed from the thysanuriform.

Ecdysis or Moulting.— AW larvae shed their outer skin (cuticula),
at intervals to allow for growth. The number of moults varies in
different insects, but is constant for the same species under the same
conditions.

In the Lepidoptera the larva is known as a caterpillar, and is char-
acterized by the possession of three pairs of true legs, and usually

Pig. 38. — Types of larvae, a. Grub of asparagus beetle; b, cutworm; c, cabbage
root maggot; d, fall canker worm;'e, maggot of honey bee; /, spring canker worm;
g, false caterpillar of saw fly; h — a, b, c, nymphs of locust; i — a, b, c, d, e, nymphs of
squash bug. {After various authors.)

five pairs of prolegs on the abdominal segments. In the Diptera and
Hymenoptera the larva is a maggot, characterized by the absence of
legs. In the group of Saw-flies of the Hymenoptera, however, the
larvae are caterpillar-like, possessing three pairs of true legs and often
seven or more pairs of prolegs.

In the Coleoptera the larva is termed a gruh, and has usually but
three pairs of legs (Fig. 38).

Classification of Larvae. — Escherich classifies larva; as follows:
Primary Larva. — Larva; like the adult, and without provisional larval organs
— Thysanura, Mallophaga, PedicuUda, Orthoptera, Isoptera, Corrodcntia.

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 35

Secondary Larva. — ^Larvae like the adult, and with a few provisional larval organs
— Ephemerida, Plecoptera, Cicadidcc, Odonata, Coccidce.

Tertiary Larva. — Larvae unlike the adult and with numerous provisional larval
organs — Lcpidoptera, Dlptera, Coleoptera, Hymcnoplera, etc.
■ Classificalion of Tertiary Larva.
A. Larvffi without prolegs.

B. Larvae with well-formed sternum.

C. Larvae more or less strongly chitinized; thorax or at least the
prothorax differing from the other segments quite noticeably,
large or more strongly chitinized, or otherwise sculptured; head
generally with lateral eye points. Examples: Rhaphidians
Ant-lions, Carabida, Dytiscida, Silphida, Coccinellida, Elalerida,
Chrysomelida.
CC. Larvae weakly chitinized, soft skinned, and mostly whitish,
but with chitinized dark head; thorax differing but little from
the other segments. Examples: White Grubs, Stag Beetles,
Dung Beetles.
BB. Larvae with poorly developed or rudimentary sternum. Examples:
Many Cerambycids, Sirex.
BBB. Larvae with sternum whoUy atrophied or undeveloped.

C. Larvae with a head-capsule and typically formed mouth-parts.
Examples: Bark Beetles, Snout Beetles, Bees, Wasps, Ants,
Ichneumons, Midges.
CC. Larvae without a head-capsule or well-formed mouth-parts.
Examples: Most Diptera.
AA. Larvae with prolegs.

B. Larvae usually with five pairs of prolegs. Butterflies and Moths.
BB. Larvae with more than five pairs of prolegs. Sawflies.

Provisional Larval Organs. — Provisional larval organs are those
which belong to the larva and not to the imago. According to Escher-
ich such organs represent adaptations for special functions, so that the
more numerous these organs are the greater the difference in mode of life
and in appearance between the larva and imago. As the imago is
older phylogenetically than the larva the larval organs have arisen in
a secondary manner.

"Secondary" larvae possess numerous imaginal characters, so that
the form of the imago remains more or less evident. In "tertiary"
larval forms the characters of the imago are so repressed by those of the
larva that a new form unlike the imago results.

Larval organization distinct from that of the imago may be observed:
(i) in the amount of chitinization, the color and the armature of hairs,
bristles, spines of the skin; (2) in the number of glands; (3) in the form

36

ECONOMIC ENTOMOLOGY

and segmentation of the body; (4) in the development of feelers and
mouth-parts, (5) in the number and development of organs of locomotion
and (6) in the alimentary, tracheal and nervous systems. Examples
can be readily found to illustrate the differences outlined above.

Pupal Stage. — After a short period of rest the full-grown larva of
holometabolic forms changes to a pupa within a pupal skin. Usually
the outer skin is shed, but sometimes, as in the Diptera, the outer skin
becomes a puparium. During the pupal stage not only are all the

Fig. 39. — Types of pupae, i. Asparagus beetle (free); 2, puparium of cabbage
root maggot (coarctate); 3, bud moth (obtect); 4, tobacco sphinx (obtect); 5, male
of maple scale (free).

external organs of the adult insect formed, but even the internal organs
undergo profound changes. The organs break down and reform, and
the structures are adapted to the new creature with its new mode of life.

In most insects the pupa is quiescent but it is quite active in the
Culicidae and other families. There is but little difference, except
the presence of rudimentary wings, between the larval and pupal
stages of the insects belonging to the Hemiptera and the Orthoptera.

Three types of pupae are recognized (Fig. 39): (i) ohtect, where the
appendages and body are closely united, as in Lepidoptera and some
Coleoptera; (2) free, where the appendages are free, as in Neuroptera,

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

37

Trichoptera, Coleoptera, Hymenoptera and Nematoceran Dipera; and
(3) coarctate in which the entire pupa is surrounded with a hardened
skin, and the appendages are not outwardly visible, e.g., higher Diptera
(Muscids, etc).

Pupas are protected in different ways: (i) in puparia, (2) in earthen
cells in the ground, (3) in a rude cocoon in wood or earth, (4) in silken
cocoons, (5): in folded leaves, (6) as chrysalids. Examples of the
above types are everywhere about us.

Internal Changes. — ^In the heterometahola the internal changes are
as direct as the external changes. In the holometabola, however, some

Fig. 40. — Stages in the hypermetamorphosis of Epicauta. A, Triungulin; B,
carabidoid stage of second larva; C, ultimate stagejof second larva; D, coarctate
larva; E, pupa; F, imago. E is species cinerea; the others are vitlata. All enlarged
except F. {After Riley, from Trans. St. Louis Acad. Science.)

of the larval organs are reconstructed into imaginal or adult tissues.
The imaginal organs arise from embryonal tissues (the imaginal buds)
which for the most part remain practically dormant in the larval stage;
in the pupal stage the purely larval organs disappear and the imaginal
organs continue their development. Histolysis is the term used to ex-
press the destruction of larval tissue by leucocytes, and histogenesis
for the construction of imaginal tissues.

Imaginal Buds.—Th.e reproductive organs, the dorsal vessel, and
the nervous system gradually mature, but many of the organs develop

38 ECONOMIC ENTOMOLOGY

from "buds" in the larva. In the caterpillar, for example, from the
inner skin or hypodermis arise buds which develop into the wings
and legs of the butterfly. In a midge or fly the head with the eyes,
feelers, and jaws, are developed by an inpushing of the skin. The food-
canal, glands, and air-tubes of a moth or a bee arise from imaginal
buds.

Imago or Adult Stage. — The pupa transforms into the imago or
adult insect. On the splitting of the pupal case the full-grown perfect
insect emerges.

(c) Hypermetamorphosis. — With some insects more than two
intermediate stages may be noted in metamorphosis. In Meloe the
young larva {triunguUn) is thysanuriform; later it resembles a lamel-
licorn larva, being cyHndrical, fleshy, and less active (the scaraboeidoid
stage), then a pseudo-pupa (the coarctate stage), and later a legless
cruciform larva. In Epicauta also triungulate, carabidoid, scara-
boeidoid and coarctate or pseudo-pupa stages occur (Fig. 40). In
Platygaster, a proctotrypid, the following supplementary larval stages
are observed: (i) the cyclops, (2) the oval, and (3) the elliptical.

Losses Due to Insects

While everyone will acknowledge the fact that damage is done by
insects, the enormity of the losses is not generally recognized. How-
ever, fairly reliable data covering such losses for several decades
in the United States are available in State and Federal records.

Every person admits large losses due to such pests as Potato Beetle,
Codling Moth, San Jose Scale, Tent-caterpillar, Cattle Horn Fly,
and Grasshoppers, but later pages will show many other injurious
forms that remain practically unobserved by the average person, on
account" of their small size, or their underground or boring habits.
The damage they do is often attributed to other causes, and frequently
reports are unreliable, unless corroborated by competent observers.

The following estimate is based on statistics prepared by experts
and published in the Year Book, U. S. Department of Agriculture.
The loss on farm products, such as cereals, hay and forage, cotton, to-
bacco, truck crops, sugars, fruits, farm forests, miscellaneous crops
and animal products, valued at 8370 millions of dollars in 1909, is
greater than 10 per cent, for there is a loss of 972 millions, not includ-

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 39

ing those in connection with natural forests and forest products, and
products in storage, which would make a probable total loss of over
one billion dollars. The losses are estimated at $1,182,000,000 for
1915, and $1,400,000,000 for 1917 (J. Ec. Ent., Feb., 1918).

Estimates of the losses inflicted by insect pests on the farm products
of Canada are mainly based on similar ones for the United States.
At the present time it is difficult to form a reliable estimate of average
annual losses due to insects from Canadian records. In some of the
older provinces fairly complete records covering a series of years
are available, but in the newer provinces the records are incomplete.

Estimates have been made of the losses from some of the more
serious pests that occasionally cause great damage, such as the Hessian
Fly and the Pea Weevil. In Ontario the loss from the Hessian Fly
in each of the years 1900 and 1901 was about two and one-half million
dollars, and from the Pea Weevil in 1902 over two millions.

If, however, the percentage loss in the United States, viz., 10 per
cent, be taken as a fair basis for insect loss in Canada it can be readily
reckoned that the total loss every year in that country exceeds 100
milUons of dollars.

Beneficial Insects

While the damage done by insects is enormous it must not be sup-
posed that all insects are injurious. As a matter of fact there are more
insects that are either beneficial or non-injurious than there are in-
jurious forms. Man owes much to the beneficial insects for their good
service in keeping the injurious forms in check.

The fact that most plants with colored flowers are largely dependent
upon the visits of insects for their fertilization and the setting of their
fruit should make it quite evident that insects play a most important
part in the economy of nature, and are no mean things after all. Let
one reflect for a moment on the loss to the world if the blossoms of apple,
plum, peach, grape, strawberry and raspberry among fruits were not
fertihzed by bees and wasps; if the clovers were not visited by
bees, and if the hundreds of beautiful wild flowers of the fields and
meadows were allowed to die without setting seeds.

In addition, one should not forget the part played by scavenger
and carrion insects that feed upon dead and decaying organic matter.
They help to make our surroundings purer and cleaner. Besides,

40 ECONOMIC ENTOMOLOGY

"insects constitute the most important portion of the food of adult
fresh water fishes, furnishing 40 per cent, of their food," according
to Dr. Forbes, of IlUnois. They also furnish food for most of our birds,
and this food may consist of many noxious forms.

There are also many insects that are decidedly beneficial, inas-
much as they prey upon injurious forms or are parasitic upon them.
At the present time a great experiment is being conducted in Massa-
chusetts for the suppression of the gypsy and brown-tail moths by the
importation of certain parasitic insects from Europe and Japan
(see Part IV). From an economic point of view it is important for
us to know the beneficial forms so that we may not unwittingly destroy
them. Few persons, perhaps, fully recognize the valuable work done
by the modest lady-bird beetles in keeping plant-Hce within bounds.
Without their intervention it is quite probable that most plants would
die from the attacks of the fast reproducing plant-lice. Ground-beetles
are also important agents in the destruction of injurious larvae, and
their value can hardly be estimated.

Beneficial insects may, therefore, be classified into:

(a) Those that prey, or are parasitic, upon injurious forms {en-
tomophagous) such as lady-bird beetles, ground beetles, parasitic
diptera and hymenoptera, etc.

(b) Those that pollinate plants, such as bees, wasps, moths, etc.
{c) Those that play the part of scavengers, feeding upon dead or

decaying organic matter, such as carrion beetles, etc.

{d) Those that serve as food for fresh-water fishes, birds, etc.

{e) Those that secrete or elaborate substances of commercial
value to man, such as honey-bee, lac insect, cochineal insect, silk-
worm, etc.

Berlese divides entomophagous insects into predatory and endopha-
goiis. Predatory insects are those which devour other insects and their
eggs outside the maternal body; while endophagous insects are those
which enter the body or eggs of their victim and destroy them.

Some entomophagous insects feed exclusively on one species, while
others feed on several species (polyphagous) . From the standpoint of
efficiency in the destruction of injurious species Berlese arranges them
in the following order :

I. Those preying on a single species and having few enemies and
aflverse factors, e.g., Novius cardinalis, Prospaltella berlesei, etc.

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 4I

2. Polyphagous endophagous species which are themselves sub-
ject to severe competition and meet with many adverse factors, e.g.,
ScutelUsta cyanea, etc.

3. Predators with special victims, e.g., many lady-birds.

4. Polyphagous predatory species; Calosoma.
Entomophagous insects include members of the Coleoptera,Hymen-

optera, Diptera, Hemiptera and Neuroptera. The coleopterous mem-
bers are the lady-bird beetles, murky ground-beetles, and tiger-beetles.

The lady-birds are small, convex, nearly hemispherical beetles,
generally red or yellow and spotted. Their antennae or feelers are
club-shaped, and their tarsi are apparently three-jointed. They feed
upon small insects and the eggs of larger species, and are specially
valuable for keeping plant-lice in check.

The larvae of lady-birds are quite active and hunt for their prey.
Some bear spines, while others are protected by fine white down.

Ground-beetles {CarabidcB) are active forms that live on the surface
of the ground. They are usually black, but some have bright colors.
They hide under stones or boards in the day-time but leave their
shelters at night. They destroy large numbers of caterpillars, such as
cutworms, canker-worms, tent-caterpillars, and the grubs of curculio.
The larvae feed underground on the larvae of leaf-feeding insects.

The ground-beetles have thread-like antennae, five-jointed tarsi,
and legs fitted for running.

Tiger-beetles {Cicindelidce) are carnivorous insects, and are most
active in the day time. Their activity, markings, and stealthy habits
have given them their common name. In structure they are closely
related to the ground-beetles, and like them have thread-like antennae
and five-jointed tarsi.

The larvae of these beetles live in holes in the ground and prey upon
unwary insects. They have large heads, immense jaws, long sprawling
legs, and two prominent humps on the back.

The Hymenoptera possess several very important beneficial forms,
mostly parasites:

Ichneumon-flies {I chneumonidce) vary greatly in size, and the females
of some species possess a protruding ovipositor. A common ex-
ample is Megarhyssa (Thalessa) a very long tailed ichneumon, which
bores a hole in wood infested with pigeon Tremex borers and deposits an
egg beside the larval Tremex (Fig. 41); other common ichneumons are:

42

ECONOMIC ENTOMOLOGY

Tragus, which parasitizes the chrysalids of Papilio; and Ophion, a
form with a compressed body, which lives on the Polyphemus moth
and yellow-necked caterpillar.

The Braconids (Braconidce) are smaller and are also parasitic. The
most common genera are Microgaster, whose cocoons are often found
on the backs of sphinx and cabbage butterfly larvae; and Aphidius which
parasitizes plant-lice.

Chalcids or chalets flies iChalcididcB) are minute metallic insects.
One species, Pteromalus puparum, is a parasite of the chrysalids of the

Fig. 41. — Female of Megarhyssa (Thalessa) ovipositing.

cabbage butterfly. Another, Aphelintis, is parasitic on scale insects
(see also p. 354).

Proctotrypids are very minute parasitic hymenoptera often prey-
ing upon the eggs of other insects.

Besides these parasitic forms there are predaceous Hymenoptera,
such as the mud-wasps, digger-wasps, wood-wasps, etc., that feed their
larvae on insects. They fill the brood cells with caterpillars, grass-
hoppers, plant-Hce, or grubs of small beetles or flies. Sphecius makes
use of cicadas as food for its young.

Several families of the Diptera are either parasitic or predaceous.
The two best known are the Tachinids and the S>Tphids.

Tachinids or tachina flies {TachinidcB) are bristly flies closely related
to the ordinary house-flies. They parasitize many kinds of caterpillars

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

43

and sawfly larvae, either by inserting eggs within the bodies of their
victims or by allowing the victims to swallow the eggs that are deposited
on leaves.

Syrphids or flower flies (Syrphidce) lay their eggs in colonies of plant-
lice which are devoured by the larvae. They are large, often bee-like
in form.

The Hemiptera include a few beneficial forms, mostly belonging
to the assassin-bug family (Reduviidce). They are predaceous, suck-
ing the blood of other insects. Sometimes higher animals, including
man, are attacked. The following forms may be noted:

Melanolestes picipes is a large black form, and Opskcetus pcrsonatus,
or masked bed-bug hunter, is black and
over 32 inch long.

The Stink Bug Family {Pentatomidce)
also furnishes a few beneficial species,
although a very large percentage of the
species is injurious to plant life. Two
common forms are: Podisus spinosus
(spined tree bug) destroys potato beetles
and currant worms, and Perillus circuni-
cinctus which appeared recently in large
numbers in potato fields where it de-
stroyed potato beetles (Fig. 42).

The Damsel Bugs (Nab idee) prey upon
leaf-hoppers.

The Ambush Bugs (Phymatidce) are
also predaceous, destroying large numbers of injurious insects.

Among the Neuroptera are some important beneficial forms,
known as aphis-lions and ant-lions.

The adults of aphis-lions, also called lace-winged flies, are readily
recognized by their delicate veined green wings. Their larvae are pre-
daceous and destroy large numbers of plant-lice. Their mandibles
are very long. The genus Chrysopa is the main one in the family.

The adults of Ant-lions {Myrmeleonidce) have "long narrow delicate
wings and a slender body." The larvae are very predaceous and possess
enormous mandibles. They capture their prey by using pitfalls.

Hyper parasitism. — It happens that many of the primary parasites
are often infested with parasites which reduce very appreciably the

Fig. 42. — Perillus circum-
cinclus, an enemy of the Colo-
rado potato beetle.

44 ECONOMIC ENTOMOLOGY

effectiveness of the primary. Frequently, however, these secondary
forms are infested with tertiary parasites.

In the control of injurious forms it is evident that primary parasites
are beneficial, secondary harmful and tertiary beneficial, on the other
hand, when beneficial insects are parasitized the primary are harmful,
the secondary beneficial and the tertiary harmful.

Insects and Birds

When it is known that about two-thirds of the food of our common
birds consists of insects, it becomes evident that the agency of birds
in the control of insects is of the highest importance. The seasonal
diet of the robin, bluebird, catbird, king-bird, flycatchers, chickadee,
wren, swallow, woodpecker, cuckoo, night-hawk, warblers, oriole and
many other birds has been carefully studied in recent years, with the
resulting discovery that insects form in most cases their only food, and
only at certain seasons are small fruits eaten.

Birds are no doubt of special value to the farmer in nipping incipi-
ent scourges in the bud on account of their ability to move rapidly from
place to place in search of food, and on account of their varied character
and habits. Especially is this true of our winter birds which search
every cranny and nook for the hibernating forms of insects at a season
when every form destroyed means in most cases the absence of hundreds
or thousands of their progeny the following summer.

An international treaty between Great Britain and the United
States for the protection of migratory birds in the United States and
Canada was signed in Washington in August, 191 6. For many years the
numbers of such birds had been decreasing to such an extent, through
careless and indiscriminate slaughter, that the agricultural and forest
crops of the two countries were in danger of suffering serious losses
from insect depredations. It was deemed advisable, therefore, in
the interests of the two countries to adopt a uniform system of bird
protection, such as the treaty provides. The most important provision
relates to close seasons, viz: (i) a close season on migratory game
birds from March loth to September ist except for maritime shore
birds when the close season is from February ist to August 15th;

(2) an open season for three and one-half months for wild fowl; and

(3) a close season throughout the year on insectivorous birds.

structure, growth and economics of insects 45

Inter-relations Between Insects and Plants

The idea of inter-relations in Nature was first emphasized by Spren-
gel, Darwin and Miiller, and later ecological studies reveal still more
clearly how all Nature is linked together into a system, one part de-
pendent upon another in an intricate web of life. Disturbances in one
portion of the system are followed by disturbances in another.
In this chapter reference is made to some of the relations be-
tween insects and plants, between insects and birds, and between
insects and their parasites. Numerous other relations might be
mentioned but these are sufficient to show that a knowledge of these
relations is an important part of the equipment of the economic
entomologist who would deal successfully with the problems confronting
him.

In a region undisturbed by man the various parts of the system of
Nature have practically reached a state of balance through the ceaseless
action for long ages of the "struggle for existence." Plant struggles
with plant, animal with animal, and both with the environment. With
the advent of man, however, the balance has been disturbed by the
clearing of the forests, the cultivation and drainage of the land, the
growing of crops, and the introduction of foreign plants and animals,
since the new set of conditions will be favorable to the increase in num-
bers of certain plants and animals, including insects, and unfavorable
to others. This disturbance is often widespread. Favored insects
will multiply rapidly on account of the abundant supply of food fur-
nished by the cultivated crops, faster at first than their parasitic enemies;
and insectivorous animals such as snakes, toads, birds and predaceous
insects will be deprived of the necessary shelter and hiding places by
the clearing of the land, and become less abundant.

On the other hand insects not favored, by the destruction of their
food plants under the new conditions, will diminish in numbers,
as will also their parasites, both sometimes no doubt to the verge of
extinction. If, however, as is sometimes the case, conditions again
favor the insect it will multiply very rapidly because the development
of the parasite lags behind its host. Moreover, there is always a
limit to the increase of the parasite, otherwise it would exterminate
its host, and eventually itself.

Many examples of inter-relationships among insects in addition

46 ECONOMIC ENTOMOLOGY

to that of parasite and host might be given. Certain ants attend
certain plant-Hce with the object of feeding upon the nectar excreted—
and not of feeding upon the plant-hce as some ignorantly suppose.
Forbes has shown that the corn-root plant-louse is actually dependent
upon the brown ant, Lasitis niger americanus, for its existence, for its
transfer to suitable winter quarters, to suitable weeds in early spring,
and j&nally to the corn itself.

In bumble-bees' nests one may often find a related bee, Psithyrus,
living as a guest and fed by the worker bumble-bees. This guest bee
is not content to live quietly in the nest; she often destroys the Bombus
queen and gets "the poor workers to rear her young instead of their
own brothers and sisters" (Sladen).

Ants' nests or formicaries often contain a motley crew of other
insects, among which are rove-beetles, pill-beetles, fly larvae, small
crickets, thieving ants, and parasites — the majority being thieves and
robbers.

Again, no satisfactory explanation has yet been given for the
preferences many insects exhibit in their feeding habits. As ex-
amples, we are at a loss to know why in some districts the wheat
midge does more damage to spring wheat than it does to fall wheat;
why the Hessian fly injures certain varieties of wheat more than
others; why the grape blossom midge injures the early varieties of
grapes most; why' the Leconte and Kieffer pears are practically
immune from the San Jose scale and the white peach scale; why
the Northern Spy apple is not troubled with the woolly aphis; why
the Red Dutch cabbages are free from the cabbage root maggot;
why the spiny elm caterpillar and the European elm scale prefer the
American elm to the imported English elm; why the European elm
saw-fly and the elm leaf beetle prefer the European elm to the
American; why the forest caterpillar attacks the sugar maple in
preference to the soft maple; why the maple scale prefers the soft
maple to the sugar maple; why the apple maggot is more injurious
to sweet and sub-acid summer varieties than to fall and winter-acid
varieties; why the brown mite is seldom seen in quince and apricot;
and why the phylloxera is more injurious to the European vine than
to the native American species.

Long-continued observations show that there are "all grades of
association between plants and insects from most casual contact to

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 47

mutual dependence, and that there are grades of fitness on both sides"
(Needham, General Biology). Reference has already been made in the
section dealing with Beneflcial Insects to the important part played
by many insects in the fertilization of plants. To this end many
beautiful adaptations occur among plants such as in legumes, iris, milk-
weed, yucca, orchids, mints, figworts, honeysuckles, canna, Smyrna
fig, etc., but it should be borne in mind that there has been also 'probably
much adaptation on the part of the insects.

Galls. — Another type of inter-relation is the galls seen on many
plants, produced by certain insects belonging to the families Cecido-
myiidee, Trypetidce, Aphididce, Psyllidce, Cynipida and Tenthredinidce.
Mites (Acarina) also produce galls. Usually an egg is laid within the
growing tissue and the larva excites the surrounding tissue to abnormal
growth. The transformations occur within the gall, and the adult
escapes to make new galls.

Galls are of various forms, often characteristic of the insects pro-
ducing them. The nutritive cells lying next to the contained larva
contain both sugar and starch and appear to function as feeders for both
the larva and the growing cells of the gall.

Insectivorous Plants. — Certain plants such as the sundew, Venus'
fly-trap, pitcher-plant and bladderwort entrap small insects and feed
upon them. These plants secrete digestive fluids which convert the
tissues of the captured insects into liquid food capable of being
absorbed.

Diseases of Insects. — Many insects are killed by the action of cer-
tain fungi and bacteria. Such diseases are frequently epidemic, and
attempts have been made to control insect infestations by the propaga-
tion and distribution of artificial cultures. Probably the best known
experiment of this nature was carried out by Dr. Snow and Dr. Forbes
against the chinch bug in the middle States by the distribution of
cultures of the fungus S porotrichum globuliferum. The result was only
moderately successful, for it was found that the disease spreads rapidly
in moist seasons, but not in dry ones when the chinch bugs are inju-
rious. There is no doubt, however, that the fungus is an important
factor in lessening the severity of the insect's attacks.

In South Africa, Algeria and Argentina the locust has been con-
trolled by the introduction of bacterial cultures of Coccohacillus

48 ECONOMIC ENTOMOLOGY

acridiorum, but in other regions where the weather conditions are not
so favorable this method has not met with success.

In the southern States the San Jose scale is often attacked by
SphcBrostilbe coccophila, but as a means of control artificial propagation
of the disease on a large scale has not been successful.

Tent-caterpillars, brown-tail and gipsy moth caterpillars are de-
stroyed in large numbers by bacterial disease.

Following is a list of the more important entomogenous fungi:

Empii$a musccB on flies, E. grylli on crickets, etc. and E. aphidis
on plant-lice. Entomophthora aphidis on plant-lice, and E. sphcBro-
sperma on many caterpillars. Cordyceps militaris on larvae and pupae
of white grubs, wireworms and some lepidopterous forms. Most of
the conidial forms of Isaria and Sporotrichmn belong to the ascus
genus Cordyceps.

Botrytis, Verticillium, Cladosporium, Mgerita and Fusarium attack
many kinds of insects, especially scale insects, plant-lice,, white flies,
and the chrysalids of moths.

Future investigations will probably lead to the better utilization
of fungi in the control of many of the most noxious insects.

Insects as Carriers of Plant Diseases

Flea-beetles by eating holes in the leaves of potato permit the en-
trance of the spores of Early Blight {Macros porium solani) with conse-
quent partial destruction of the leaves. It has also been shown fairly
conclusively that certain aphids and other insects^ act as carriers of
Twig Blight {Bacillus amylovorus) of apples and pears, that the
beet leaf-hopper {Eutettix tenella) transmits to sugar beets the " Curly
Leaf" disease, and it is now believed that the squash bug {Anasa
tristis), the striped cucumber beetle {D. vittata), the 12-spotted cu-
cumber beetle {D. 12-punctata), the cucumber flea-beetle {Epitrix
cucumeris), the melon aphis {Aphis gossypii), and the 12-spotted
lady-beetle {Epilachna borealis) frequently inoculate the stems of cucur-
bits with the cucurbit wilt {Bacillus tracheiphilus). Again, the punc-
tures made by the plum curculio in plum, cherry and peach permit
entrance of the spores of the Brown Rot Disease {Sclerotinia fructigena) ,

^ Gossard mentions among others Aphis avencE, Empoasca mali, Eccoptogasler
rugulosus, and Lygus pratensis. "Any sucking insect can become a carrier, also any
insect with the bark-burrowing habit."

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 49

and Ihe greenhouse white fly {Aleyrodcs vapor arionim) often transmits
the disease Cladosporiuni fulviim to tomatoes.

Tree crickets {QLcanthus) are said to be responsible for the inocula-
tion of trees and shrubs with canker, of raspberries with the cane
blight, and probably for the production of other diseases.

Insects and Disease

(Consult Handbook of Medical Entomology by Riley and Johannsen, and
Medical and Veterinary Entomology by Herms.)

During the last twenty years important discoveries have been made
regarding the transmission of certain diseases by arthropods such
as the mosquitoes, house-flies, stable-flies, gad-flies, tsetse-flies, fleas,
bed-bugs, lice and ticks.

Insects and arachnidans cause disease in one or more of the fol-
lowing ways: by direct infection, that is by the introduction of a patho-
genic organism into the circulation, as in the case of the malarial
mosquito, the yellow fever mosquito, the sleeping-sickness flies,
horse flies and others; by indirect infection, that is by infecting food,
as in the case of the house-fly; by internal parasitism as in the case of
warble flies and bots; by external parasitism as in the case of lice,
fleas, bed-bugs and ticks ; and by the introduction of poisons as in the
case of bees, wasps, kissing bugs and others.

Brues and Sheppard have divided the diseases that are carried by
insects into three groups:

Group A. — Characteristically insect-borne diseases.

Group B. — Often insect-borne diseases.

Group C. — Possibly insect-borne diseases.

Under Group A are included malarial fever, yellow fever, filariasis,
sleeping sickness, typhus fever, bubonic plague, African tick-fever,
Rocky Mountain spotted fever of man, and Nagana and Texas fever
of horses and cattle.

Under Group B. are included typhoid fever, cholera, dysentery,
diarrhoea, tuberculosis, septicaemia.

Under Group C. are included anthrax, rabies, pellagra, hookworm,
beriberi, black water and relapsing fever of man; and equine infectious
anaemia.

50 ECONOMIC ENTOMOLOGY

A nopheles Mosquito and Malaria:

Malarial fever and ague were common a generation ago, and our
fathers vaguely attributed the disease to the presence of swamps
whose numbers have fortunately been greatly reduced by drainage.

The story of the discovery of the causal organism and of its life-
history in connection with the Anopheles mosquito is one of the in-
teresting chapters in modern biological investigation. The organism
belongs to the amoeboid Protozoa and was discovered by Laveran,
a French army surgeon, in 1880. The part of Anopheles as a second
or intermediate host of the malarial organism was worked out later
by Doctors Manson and Ross. (A full account of the discovery will be
found in Kellogg's "American Insects.")

The malarial plasmodium on gaining access to the human body
lives within a red blood-corpuscle and thrives at the expense of the
haemoglobin. A characteristic excretory product in affected cells
is the black granules of melanin. In 48 hours the plasmodium reaches
maturity and divides into many spores, termed merozoites, which are
set free in the blood. These soon enter new blood-corpuscles and
reach maturity in 48 hours as before. This production of spores coin-
cides with the characteristic "chill" of ague, and is followed by a fever
when the spores enter the blood-corpuscles. As a result of the de-
struction of the red blood-cells the patient becomes anamic. Certain
of these spores, however, make no attempt to enter new blood-corpuscles
and may remain in the blood for an indefinite period. These are the
gametes — the micro- and macro-gametes — which, if taken into the
stomach of an Anopheles mosquito, will, however, undergo further
development. The male or micro-gamete produces a number of
whip- like threads or fiagellce, which are capable of uniting with the
female or macro-gametes, producing vermicules or ookinetes. These
penetrate into the wall of the stomach of the mosquito where they
rest as cysts, forming little lumps on the outer surface. These cysts
mature in about ten days and burst, liberating large numbers of
sporo-blasts into the body cavity, whence they find their way to the
salivary glands. When such an affected mosquito bites a human
being these spores are injected into the blood and enter the red cor-
puscles. It will be seen, therefore, that ordinarily the Anopheles
mosquito is the only agency for the transmission of malaria to man
(Fig. 43)-

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 5 1

Fig. 43. — Life history of malaria parasite, Plasmodium prcecox. i. Sporozoite,
introduced by mosquito into human blood; the sporozoite becomes a schizont. 2.
Young schizont, ^hich enters a red blood corpuscle. 3. Young schizont in a red
blood corpuscle. 4. Full-grown schizont, containing numerous granules of melanin.
5. Nuclear division preparatory to sporulation. 6. Spores, or merozoites, derived
from a single mother-cell. 7. Young macrogamete (female), derived from a mero-
zoite and situated in a red blood corpuscle. 7a. Young microgametocyte (male)
derived from a merozoite. 8. Full-grown macrogamete. 80. Full-grown micro-
gametocyte. In stages 8 and 8a the parasite is taken into the stomach of a mos-
quito; or else remains in the human blood. 9. Mature macrogamete, capable of
fertilization; the round black extruded object may probably be termed a "polar

52 ECONOMIC ENTOMOLOGY

Stegomyia Mosquito and Yellow Fever:

The demonstration of the causal relation between the Stegomyia
mosquito and yellow fever is another interesting story, and was worked
out mainly by Major Walter Reed of the U. S. Army Medical Service
in Cuba in 1900 and 1901. In his experimental camp Major Reed
and his associates proved that yellow fever could not be transmitted
by contact with yellow fever patients, but only by the bites of infected
mosquitoes and by the artificial injection of diseased blood. The
causal organism has not yet been discovered on account of its being a
filterable virus. It is known, however, that a 12-day incubation
period is required in Stegomyia before its bite becomes infectious to a
second person. Moreover, the mosquito can obtain infected blood
from a patient during only the first three days of his disease.

Based on these facts, the control of yellow fever has become an
easy matter. The patients are isolated as soon as the disease appears,
and standing water in which Stegomyia might develop is treated with
kerosene. Besides, all rooms in the building and adjacent buildings
are fumigated, for the purpose of destroying living mosquitoes.

Culex Mosquito and Filariasis:

The tropical disease, filariasis, is caused by a minute nematode
worm, Filaria, which lives in the blood of man and certain species
of Culex (C. fatigans). The worms escape from the mid-intestine of
the mosquito into the muscular tissue where they grow for two or three
weeks. They then migrate to other portions of the body and often
collect at the base of the proboscis, whence they are carried into the
human blood circulation. Sometimes the worms become three or
four inches long and obstruct the lymphatic canals, causing elephan-
tiasis, characterized by enormous sweUings of the legs, arms and other
parts of the body.

body." ga. Mature microgametocyte, preparatory to forming microgametes. gb.
Resting cell, bearing six flagellate microgametes (male). lo. Fertilization of a
macrogamete by a motile microgamete. The macrogamete next becomes an ookin-
ete. II. Ookinete, or wandering cell, which penetrates into the wall of the stomach
of the mosquito. 12. Ookinete in the outer region of the wall of the stomach, i.e.,
next to the body cavity. 13. Young oocyst, derived from the ookinete. 14. Oocyst,
containing sporoblasts, which are to develop into sporozoites. 15. Older oocyst.
16. Mature oocyst, containing sporozoites, which are liberated into the body cavity
of the mosquito and carried along in the blood of the insect. 17. Transverse section
of salivary gland of an Anopheles mosquito, showing sporozoites of the malaria para-
site in the gland cells surrounding the central canal.

1-6 illustrate schizogony (asexual production of spores); 7-16, sporogony (sexual
production of spores). {After Grassi atid Leuckarl, by permission of Dr. Carl Chun.)

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 53

House-fly and Typhoid Fever:

Much attention has been directed in recent years to the dangers of
the house-fly (Musca domestica) and other flies as agents in the trans-
mission of disease. All Public Health Departments now take cognizance
of the house-fly and issue warnings against its presence about the home.
Epidemics of typhoid and cholera in many cities, as well as the out-
breaks during the Spanish- American war brought out the fact that the
house-fly was largely responsible for the troubles.

The habits of this insect are such as to make its presence dangerous.
It breeds in filth, and as an adult fly it feeds on all kinds of decaying and
fecal matter as well as the sweets and liquids of the dining table.
Its feet and proboscis are admirably adapted for carrying those bacterial
germs that cause typhoid fever, cholera, dysentery, diarrhoea, tubercu-
losis, etc. Moreover, it has been shown that typhoid bacilli swallowed
by the house-fly when it feeds on and crawls over contaminated sub-
stances survive the passage of the alimentary canal, so that "fly-
specks" may contain many active typhoid germs.

It has been shown that several other species of flies that frequent
houses may also convey typhoid bacilli. The "little house-fly"
(Fannia canicularis) , the Latrine-fly {Fannia scalaris), the blow-fly
(Calliphora erythrocephala) , Muscina siabulans, the cluster-fly (Pol-
lenia rudis), and the stable-fly (Stomoxys calcitrans) have all been found
guilty and precautions should be taken to guard against their presence.

The charges proven against the house-fly as an active agent in dis-
seminating not only typhoid fever but also cholera, dysentery and tu-
berculosis are overwhelming. This insect pest should, therefore,
be banished from our midst. If we do not care for our own health
we should at least protect the helpless children who are perhaps the
greatest sufferers.

(For further particulars the excellent works of Doctors Hewitt
and Howard should be consulted.)

Anthrax and Infantile Paralysis:

The stable-fly {Stomoxys calcitrans), the horn-fly (Hcematobia
serrata), gad-flies (Tabanus and Chrysops), and the black-fly (Simulium)
have both piercing and sucking beaks and are true blood-suckers. As
such they are liable to introduce virus into the human blood. Anthrax
is a disease of many domesticated animals and of man; and it is
believed that these blood-sucking flies are agents of transmission

54 ECONOMIC ENTOMOLOGY

by inoculation forming malignant pustule; but the pulmonary and
intestinal forms of the disease require other methods of infection.

In the recent outbreaks of acute anterior poUomyeHtis or infantile
paralysis in different parts of the United States and Canada the stable-
fly was strongly suspected at first of being the transmitter of the causal
organism. Later, however, in many experiments in which monkeys,
rabbits and other rodents were inoculated by stable-flies caught in
the wards of hospitals containing poliomyelitis patients, and flies that
had fed on animals inoculated with the virus were allowed to feed upon
healthy animals, no symptoms of the disease developed. Besides,
the disease spread on some occasions in mid-winter when stable-flies
could not be active agents. The present opinion is that insects play
a subordinate role, if any, in spreading the disease and that it is trans-
mitted by contact with infected persons. The causal organism has
not yet been isolated, being filterable and ultra-microscopic like that
of yellow fever.

Tsetse-flies and Trypanosomiasis:

Tsetse-flies (Glossina spp.) are not native to America, but belong
to tropical and sub-tropical Africa. They are blood-sucking flies,
closely related to stable-flies, and in- recent years have been shown
to be causally related to severe diseases of both man and domesticated
animals. Dr. Bruce made the important discovery that nagana, a
very fatal disease to horses, cattle, dogs and donkeys in South Africa,
was produced by a trypanosome carried to the blood by the bites of
tsetse-flies. These trypanosomes are flagellate protozoa, and when
they occur in the blood of certain warm-blooded animals set up a dis-
ease called trypanosomiasis. They are carried from one host to another
by certain invertebrates, such as mosquitoes, lice, fleas, and especially
by such blood-sucking flies as the tsetse-flies.

The Nagana disease is caused by Trypanosoma brucei and the tsetse-
flies mostly concerned are Glossina morsitans and G. pallidipes.

In the Congo Basin of Central Africa the terrible "sleeping-sickness"
disease carries off tens of thousands of natives every year. Doctors
Forde and Dutton isolated the specific causal organism of this disease,
which was named Trypanosoma gambiense, and Bruce and Navarro
traced the organism to the bite of the tsetse-fly, Glossina palpalis.
Folsom states: "In the first stage of the disease, marked by the appear-
ance of trypanosomes in the blood, negroes show no symptoms as a rule,

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 55

though whites are subject to fever. The symptoms may appear as
early as four weeks after infection or as late as seven years.

"In the second stage trypanosomes appear in the cerebro-spinal
fluid and in large numbers in the glands, those of the neck, axillae and
groins becoming enlarged. There is tremor of the tongue and hands,
drowsiness, emaciation and mental degeneration. The drowsiness
passes into periods of lethargy which become gradually stronger until
the patient becomes comatose and dies. Some victims do not sleep
excessively but are lethargic and profoundly indifferent to all going
on around them."

Late investigations go to show "that Glossina morsitans may act
as a host for a human trypanosome which is probably identical with
T. gambiense." Probably also " that some of the vertebrates other than
man may harbor T. gamhiense and that there is a possibility of these
things being transmitted to man" (Doane).

With regard to the development of T. gambiense in Glossina palpalis
it is known that "two days after biting an infected animal the fly
becomes mcapable of mfectmg other animals and remains so for about
22 to 28 days, when it again becomes infective and may remain so for
at least 96 days. During the infection period the salivary glands are
found to be invaded with the type of the trypanosome that is found
in the vertebrate blood" (Doane).

Rat Fleas and Plague:

Plague, known in three forms as bubonic, septicaemic and pneu-
monic, is caused by Bacillus pestis which attacks rats, mice, cats, dogs
and other animals. The disease is transmitted mainly by fleas, some-
times by bed-bugs, and the wounds made by the bites allow entrance to
plague bacilli. "Plague is primarily a disease of rats, an epidemic of
plague in these animals having often been observed to precede as well
as to accompany an epidemic among human beings."

The recent outbreak of pneumonic plague in Manchuria showed an-
other phase of infection. This disease is not dependent on fleas for
its transmission, but it could be traced to an outbreak of plague in the
tarabagans or marmots, a kind of squirrel. Dr. Cantlie says that Plague
may develop or appear in the following stages: (i) as a disease in ani-
mals; (2) as pestis minor conveyed by infected insects; (3) bubonic
plague, sporadic cases, carried from animals to man by insects; (4) epi-
demic bubonic plague carried from man to man by insects; and (5)

56 ECONOMIC ENTOMOLOGY

pneumonic plague passing from man to man directly, or conveyed by
insects. Dr. Kitasato is quoted as saying that the (Manchurian)
pulmonary plague cannot spread through the air as the digestive
tract is plague-proof, and that direct contact is necessary.

Lice and Certain Diseases:

Typhus fever is transmitted from man to man by the Body Louse
{Pediculus vestimenti), and Beriberi probably by the Head Louse

{Pediculiis capitis) .

Ticks and Certain Fevers:

Although ticks are not true insects yet they have been considered
as coming under the field of the entomologist. In certain western
states, viz., Montana, Idaho, Wyoming, Utah and Nevada, the Rocky
Mountain Spotted Fever occurs and is produced by the bites of ticks
{Dermacentor venustus, et al.) which carry spirochaetes. The African
tick-fever is carried by another tick {Ornithodoros moubata), the
African Relapsing fever possibly by a tick, the African East Coast
fever of cattle by ticks (Rhipicephalus appendiculatus) and the Texan
fever of cattle by a tick (Margaropus annulatus) inoculating cattle
with the protozoan spirochjete Babesia bovis, a fact observed by Dr.
Theobald Smith.

Other Diseases:

The terrible "hookworm" disease of the South is probably carried
by the common house-fly. The causal organism {Anchylostoma
diiodenale) a round worm may also enter the skin from infected soil.
Pellagra is transmitted, according to many authorities, by the bites of
species of black-fly {Simulium) or by the ingestion of mouldy corn.
White grubs (Lachnosterna) are hosts for the thorn-headed worm
{Echinorhynchus gigas) and food for swine which in turn becomes
food for man.

Leprosy, that most dreaded disease, is now believed to be trans-
mitted by flies, fleas, mosquitoes and bed-bugs. Possibly also certain
mites may be occasional carriers of the bacillus {B. leprcs).

It will be seen from this account that the insects concerned in the
transmission of disease are of two kinds: those, like the mosquito which
transmit malaria and filiariasis, which are essential hosts of the disease
organisms, and those which transmit the disease mechanically. Any
insect which habitually attacks man or which may enter the house or

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 57

milking stable after having fed on human excreta is potentially a
disease vector, so that we cannot too strongly emphasize the necessity
of keeping all foods adequately screened and of preventing such insects
as house-flies, blow-flies or mosquitoes from entering human dwellings.

Besides carrying disease germs many insects may themselves cause
disease in man. Many mites, lice and fleas cause dermatitis, scabies
or ulcers in man. The larvae of many flies, notably the blue bottles,
blow-flies, flesh flies and bot flies, cause intestinal, dermal, muscular,
nasal or auricular myiasis in man.

MacGregor in a recent paper (Bui. Ent. Res., Vol. viii, pp. 155-163)
lists eighty organisms causing disease which may be transmitted by
insects.

Insect Behavior Toward Stimuli

In recent years a large mass of facts regarding the behavior of insects
toward their environment — both organic and inorganic — has been
collected, and in a few cases this information has been of service in the
control of injurious forms. In general, however, the application of such
methods of control is still in its infancy stage, but it gives promise of
valuable results in the near future.

As the relations of insects to plants and to other insects have been
discussed in previous sections attention will be confined here to the
behavior of insects under the influence of environmental stimuli, such as
light, heat, moisture, chemical contact, winds, etc.

For some time it has been known that plants show tropistic move-
ments with regard to light, heat, gravity, moisture, contact, etc.
Moreover, some progress has been made toward an understanding
of the processes. Plants, for example, bend toward the light because
the cells on the side away from the light grow faster than those on the
side next to the light. There is no conscious control of the movement
by the plant. Animals, too, exhibit movements under the influence of
tropic or taxic^ stimuh. In the case of insects, butterflies, bees, house-
flies, and many moths and caterpillars are positively phototropic or
phototactic and move toward the light, while maggots, bed-bugs and
cockroaches move away from the light.

* The term taxic is now more commonly used than Iropic when applied to the
locomotor movements of animals under the action of stimuli, Iropic being usually
reserved for the turning or orienting movements.

58 ECONOMIC ENTOMOLOGY

Again, most moths move away from sunlight but move toward a
lesser light such as electric or oil lamps. Davenport explains this
difference by saying that " butterflies are attuned to a high intensity of
light, moths to a low intensity." Loeb explains the circling of moths
and other insects about a light. The stimulus orients the insect by its
more intense action on the muscles next the light, and the insect then
moves toward the light.

Loeb states that caterpillars of the brown tail moth as they emerge
from hibernation in spring are positively phototropic, but after they
have eaten this response disappears, showing that taxic reactions are
sometimes dependent on the state of the body.

"Swaine finds that the destruction of piled logs by the wood-boring
larvae of the sun-loving Monohammus can be prevented by forming a
dense shade over the logs by means of brush. In his study of the army
cutworm {Euxoa auxiliaris) in Alberta, Strickland found that the larvae
are negatively phototropic and hide beneath the soil till about four or
five o'clock in the afternoon when they come to the surface to feed.
With the weaker light they become positively phototropic and a
general migration in a westerly direction takes place. When food is
scarce hunger may overcome their aversion to sunshine with the result
that the larvae come above ground, but they still display a modified
negative phototropism and migrate in a northwesterly direction.
These facts are of practical value in controlling outbreaks of this insect
(Hewitt)."

Insects are very responsive to the stimulus of heat, i.e., they are
thermotactic.

Some insects respond to the stimulus of touch or contact, and
are said to be either positively or negatively thigmotactic. Cock-
roaches are in the habit of squeezing into narrow crevices, and Loeb
mentions the case of a moth Pyrophila which also has the same habit.
Chemical substances and foods also act as stimuH influencing the
movements of insects. Maggots orient themselves with regard to
their food and then move toward it, the orientation being the result of
unequal chemical stimulation of the muscles of the two sides of the
body. The deposition of eggs by most insects on certain plants is also
the result of chemotropism. The house-fly and many piercing insects
such as the biting flies and mosquitoes are repelled by phenol and other
coal tar products.

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 59

Wheeler and Loeb give several examples of geotropism among
insects. They observed that lady-birds and cockroaches at rest
placed themselves on vertical rather than horizontal surfaces.

Observations show that taxic reactions are very adaptive. Ants
and aphids are positively phototaxic when they get wings; and honey
bees are periodically phototaxic, thus leading to swarming. Ants,
moreover, are strongly thermotaxic, thus securing for their brood the
optimum temperature conditions.

Relation of Insects to Temperature and Humidity

Two important factors influencing the life of insects are temperature
and humidity. Their general regulatory action has been known for a
long time, but scientific data obtained in recent years enable us to
speak more definitely regarding the behavior of insects toward the
varying temperature and humidity of their environment.

Pierce in his studies of the cotton boll weevil and other forms
says: ''A careful study of the records of any species, charting for the
time required for each activity and the temperature and then similarly
for the humidity, will disclose temperature and humidity points of
maximum efiiciency. With the boll weevil these points lie approxi-
mately near 83°F., and 65 per cent, relative humidity."

Ewing has found that a constant temperature of go^F. prevents
the development of Aphis avencB, and that the optimum temperature
for the production of the wingless agamic forms is about 65°F.

The larvae of the common house-fly are killed at a temperature of
io5°F., and the close-packing of manure is sufficient to prevent the
breeding of flies.

With regard to changes in humidity, insects vary somewhat widely
in their reactions. For example, moist air is favorable to most aphids
and hastens the development of the larva of the Hessian fly. On the
other hand, dry seasons favor the development of the chinch bug
and wheat midge.

Gardeners and florists have long observed that red spiders and most
species of thrips are more abundant, and hence more injurious, under
warm dry conditions.

The investigations of Bachmetjew show that humidity is an im-
ortant factor modifying the effects of temperature, and that the

6o ECONOMIC ENTOMOLOGY

metabolic activities of insects are related to both temperature and
humidity. He says: "Apparently there is a degree of atmospheric
humidity which being the most favorable to the maximum speed of
insect metabolism should be designated as the optimum; that this opti-
mum varies for each species, for each stage of each species, and for
each stage of each individual."

The codling moth is an example of a common insect whose develop-
ment is greatly influenced by weather conditions. Even within the
limits of a single state or province the rate of its development and the
time of its stages are influenced by latitude, by early and late seasons,
by cool and warm seasons, and by wet and dry seasons. The student
will find in the observations of Simpson in Idaho, Pettit in Michigan,
Sanderson in New Hampshire, Hammar in Pennsylvania and Michigan,
Jenne in Arkansas, Caesar in Ontario, Headlee in Kansas, Siegler and
Simanton in Maine, Brooks and Blakeslee in Virginia, and Forbes
in Illinois much valuable data for investigations on the relation of
insects to climatic factors.

The Distribution of Insects

On account of the large increase of international trade many economic
forms of importance have been introduced into Canada and the United
States from other countries, and as it is a matter of pubHc interest
to know if such imported forms are likely to become injurious con-
siderable attention has been given of late years to the investigation
of this problem. The problem is not yet completely solved, but
progress may be reported.

The common natural means of dispersal are flight, wind, animals,
and railways, etc. Many insects are able to fly long distances, many
are carried by wind currents and many are transported on materials
of commerce. A few examples of such dispersal may be cited. The
brown-tail moth is a good flyer, and is thus able to spread rapidly.
On the other hand, the female of the gipsy moth cannot fly, consequently
the spread of this insect follows the lines of trade. It has been observed
that the Hessian fly spreads most readily in the direction of the pre-
vailing winds at the time of the emergence of adults, and that the larvae
of the San Jose scale are carried by the winds. Again, warble and bot
flies are transferred from one district to another by their hosts. Man

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 6 1

himself is responsible for the carrying of lice from district to district,
often resulting in war time in serious epidemics.

The Colorado potato beetle migrated eastward from its home in
Colorado, preferring the cultivated potato to the wild solanums, and
the asparagus beetles followed the lines of travel westward from the
Atlantic.

On the other hand, there are many barriers to the spread of insects:
oceans, seas, mountain ranges and deserts are natural barriers and
tend to prevent wide distribution. Climatic conditions, such as
temperature and moisture, are also very important factors in insect
distribution, often indirectly due to the absence of suitable food plants.
The chinch bug and the Rocky Mountain locust, for example, do
not thrive under moist conditions.

As the habits of insects are very variable, some being limited,
others almost cosmopolitan in their distribution; some sensitive to
•emperature and moisture extremes, others more or less indifferent
to these factors; some feeding only on one or two hosts, others more
or less general feeders and therefore not so likely to be restricted in
their range, the problem of the determination of probable insect
distribution is not an easy one to solve. Moreover, the presence or
absence of parasites complicates the problem.

Dr. Merriam's map of the Life Zones of North America shows
the distribution of birds and mammals and plants into seven zones
running east and west, viz.: Arctic, Hudsonian and Canadian oi the
Boreal region; the Transition, Upper Austral and Lower Austral of
the Austral region; and Tropical (see Map).^ It must be understood,
however, that the boundaries of these zones are not hard and fixed,
for there is necessarily an overlapping to some extent. It is interesting
to note that the great agricultural areas of Canada and the United
States lie mainly in the Transition and Upper Austral zones. Recent
studies go to show that in general insects tend to conform to the same
zonal distribution, although several forms, such as the house-fly,
mosquito, chinch bug and army-worm, range through several zones.

^ Merriam states the laws of temperature control as follows:
I. "Animals and plants are restricted in northward distribution by the total
quantity of heat during the season of growth and reproduction; and 2. "Animals
and plants are restricted in southward distribution by the mean temperature
of a brief period during the hottest part of the year."

62

ECONOMIC ENTOMOLOGY

-^:::^^^^;5:^^«^S^^W^

^..;#

rc>e.V^

^^S^^

^^

I ^ I'.n,!.. .UI.AI. M IM KV

/-oNK. .\l \l' "I- NciKI'll AMKKli-A

Fig. 44. — Map of North America showing the life zones. (After Mo riam.)

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 63

As a rule, however, insects diffuse most readily in the zone in which
they originated, and in the direction of least resistance. The Transi-
tion and Austral zones are differentiated into an eastern humid, a
western arid and a Pacific humid division and certain insects occur in
one division and not in the others.

As examples of the economic importance of a study of the factors
of distribution of insects the cases of the imported elm-leaf beetle
and San Jose scale may be given. Fernald says:

"The Elm-leaf Beetle . . . thrives in the Upper Austral Zone, but is
noticeably absent in the highlands of the Pennsylvania mountain regions,
though it is present again west of them. To the north it has caused serious
loss to the elms of New England, resulting in the appropriation of large
sums for spraying of the trees to protect them from its ravages. Careful
studies of this pest in Massachusetts show that while a serious menace to the
life of the elms in the southern part of the state and in the river valleys, it
becomes of little importance in the higher and northern parts, and many
towns which formerly appropriated money for the protection of their elms
from this insect have now learned that this was unnecessary, as the trees
would suffer but Uttle at most, in any case.

"With the San Jose Scale similar facts are now coming to light. This
pest finds the best conditions for its hfe in the Lower and Upper Austral
Zones, where it has caused the loss of many millions of dollars. Even in the
Upper Austral territory of Massachusetts, it is one of the most destructive
enemies of the fruit-grower. As we pass into the Transition Zone, however,
its ravages become less severe, and by the time the centre of this zone has
been reached it is of only medium importance. In this case it has seemed to
those studying this problem that this insect was originally limited by the
Upper Austral, but has gradually acquired some degree of resistance to
lower temperatures and has thus been able to extend into the Transition
Zone."

As Webster has shown, the migration and diffusion of insects have
occurred along four main lines. The first was from the east by way of
New York or one of the North Atlantic states and the open pathway
into the interior past lakes Ontario and Erie. Examples of such
migration are the imported cabbage butterfly, the two species of
asparagus beetles, the clover-leaf weevil, the clover-root borer, the
Hessian fly, the horn fly and the willow curculio. The second line was
northward from the West Indies by way of Florida up the Atlantic
coast, bringing in many beetles, scale insects, the harlequin cabbage
bug and other Hemiptera. The third Hne was northward from Central

64 ECONOMIC ENTOMOLOGY

and South America by way of Mexico, passing up the Mississippi
valley or up the western valleys. Examples of such migration are the
Diabroticas, the cotton boll weevil, the Argentine ant, the potato
beetle, Halisidota, harlequin cabbage bug and the chinch bug. The
fourth was southward from Asia by way of Alaska. Examples of such
a diffusion are certain lady-birds, Lina spp. and Silpha spp.

Regarding the fauna of British Columbia E. M. Walker believes it
represents a mingling of Asiatic, Californian and Mexican types.

With regard to insects that have come in from foreign countries
it is generally true that they confine themselves to zones similar to those
from which they have come. Of these mention may be made of Crio-
ceris asparagi, Pieris rapce, Hylastinus obscurus, the warble" and bot
flies, the San Jose scale, and the gypsy and brown-tail moths. Some
forms, such as the codling moth and other insects, tend to become cos-
mopolitan, but they seldom become epidemic outside of their special
zones.

Similarity of climatic conditions in corresponding zones of two
continents renders it easy for species introduced from one to the other
to gain a footing, as the absence of native parasites affords an oppor-
tunity for excessive multiplication.

The influence of elevation on the distribution of insects is seen in
the southward extension of the zones in hilly or mountainous regions.
In an understanding of the distribution of many northern forms often
isolated on summits south of their normal zone geological history comes
to our aid. The great Tertiary extension of land areas in the north-
east and the northwest, making land connections with Europe and Asia,
permitted northern forms from these continents to pass to America,
and the advance of the Great Glacier southward during the Glacial
Period forced many northern forms southward, some of whom were
left stranded on mountain summits on the retreat of the ice.

Methods of Studying Economic Insects

It has been already pointed out that one of the characteristics of
modern-day investigations in economic entomology is the introduction
of the "field station" method, whereby each pest is studied under
natural conditions both in the open field and in the laboratory. By
this method it is possible to study all or most of the factors that play
a part in the life of both host and pest. No phase is too trivial for

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 65

examination, for it may sometimes happen that apparently trivial
and minor factors turn out to be important; for example, the discovery
of a preoviposition period for many Diptera furnishes a means of con-
trolling them at this vulnerable period.

An important part of the equipment of the economic entomologist
is a knowledge of the principles of "ecology" which enables him to
analyze and scrutinize the various factors that play upon insects. The
ecological sciences that have a more or less direct bearing upon economic
entomology are Botany, Zoology, Chemistry, Physics, Geology and
Geography, and their outgrowths, Bacteriology, Forestry, Meteorology,
Physiology, and the group termed Agriculture.

While a knowledge of these sciences is valuable in the study of in-
sect problems it must necessarily be general in its character and in-
sufficient for the solution of many of the more difficult problems. The
worker should, therefore, confer with speciaHsts in other depart-
ments. Especially is this necessary in deahng with measures of con-
trol. Sometimes recommendations are made which are at variance
with the most approved farm practice. By consultation with an
agronomist, horticulturist or forester such conflicting recommenda-
tion would not be given to the pubHc but would first be revised to
meet all requirements.

In the study of insects of farm crops, for example, the investigator,
working along his own line, frequently reaches a position where he
cannot make further progress without more information from workers
in other branches and from experienced farmers. Such information
may relate to methods and action of fertilizers, methods of cultivation
and rotation, meteorological and physiographic influences, and the
practical application of measures of procedure. Similarly in dealing
with orchard insects progress in investigation can only be made when
there is full co-operation with the expert horticulturist, the orchardist,
the pathologist and others, who are able to give valuable advice and
assistance.

As one might expect, every kind of insect demands its own par-
ticular method of investigation, for no two kinds of insects are oper-
ated upon by the same factors. Hence the successful investigator must
be able to contrive simple but effective devices for the determination of
the various factors. Costly insectaries and appliances are not abso-
lutely necessary; on the other hand, the tendency among the best work-

66

ECONOMIC ENTOMOLOGY

ers is to use inexpensive appliances. The most important consideration
in the rearing of insects for the purpose of ascertaining their Hfe history
is to make conditions as nearly natural as possible. Cages of various
kinds covered with muslin or wire netting are in common use. Some
may be flower pots and lamp chimneys in which the host plants are

Fig. 45. — Types of underground breeding cages, i, 15-inch pots with wire
^^screen cover tops; 2, 15-inch pots with cyhnder-shaped tops. (After Davis.)

growing; others, breeding cages of larger size and more elaborate
construction.

In the study of underground forms such as white grubs and wire-
worms the cages are usually buried to the full depth in the earth,
Davis has found large flower pot cages, deep cylinder-shaped cages and

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

67

Fig. 46. — Insect breeding cage, a, Sliding glass door; b, galvanized iron base;
c, galvanized iron holder for records; d, wooden base; e, wooden bottom detachable.
Sides are covered with cheesecloth. {After Webster.)

Fig. 47. — A gasoline or electric trap lantern with attachment of four cups for
nsects, which fit into each other and are separated by netting of different sizes, and
one for cyanide at the bottom. {After photo by Davis.)

68

ECONOMIC ENTOMOLOGY

cages constructed of wire gauze useful. One-ounce tin salve boxes
are employed to study the habits of the grubs, their growth and
moults.

In the breeding of aphids and other insects which readily succumb to
heat, the cages are placed in "shelters" covered with a canvas screen
so as to permit free air circulation (Figs. 45-49)- When trees are
convenient the shelters may be placed under them and the screens
removed.

The rearing and distribution of parasites of insects demands special
contrivances which may be easily made. Much valuable information

Fig. 48. — Insectary and aphid breeding shelter, shuwiug canvas curtain rolled up.

{Photo by J. J. Davis.)

is available as a result of the experiences of the workers in the Parasite
Laboratory at Melrose Highlands, Mass.

The economic entomologist should be a good photographer, and the
laboratory should possess a full photographic outfit and a dark room.
Camera records are among the most valuable.

A very important part of the work of the investigator is the keeping
and filing of records of the collections, experiments and observations.
Two catalogues of the collections — the Accessions Catalogue and

STRUCTURE, GROWTH AND ECONOMICS OF INSECTS

69

the Species Catalogue — and an Experiment Record of the experiments
that are conducted should be kept. The Loose-leaf filing system is one
that is admirably adapted for these purposes.

The observational notes are best made on separate detachable slips
of a note book that can be conveniently carried in the pocket. These
slips are torn off and filed in card index trays under the name of the
insect discussed. This method saves unnecessary transcribing, is

Fig, 49. — A large breeding cage used in the study of locusts, army worms, etc.
{Photo by J, J. Davis.)

simple, and serviceable in matters of correspondence and the prep-
aration of reports and bulletins.

Three types of collections should be made: (i) the reference collec-
tion in standard cases such as the Schmitt, the Comstock or other form
of box in which the specimens are arranged in systematic order accord-
ing to the latest check lists; (2) the economic collection where the speci-
mens are arranged according to host, where the life-stages and the work
of the insect are given prominence; and (3) the illustrative collection
in Riker mounts for lecture purposes.

PART II

TABLES FOR THE IDENTIFICATION OF INSECTS INJURIOUS TO FARM,
GARDEN AND ORCHARD CROPS, ETC.

I. INSECTS INJURIOUS TO CEREAL CROPS

{Wheat, Rye, Barley, and Oats)
(Consult Bull. 52 C. E. F. Ottawa, Bull. 44 W. Va.. and Farmers' Bull. 132 U. S. Dep. Ag.)

Roots:

(a) Plants stunted, yellow, and withered or dead; roots eaten.

1. Smooth, slender, wire-like, six-legged worms present in the soil. — Wire-
worms, p. 293.

2. Presence in the soil of large soft-bodied whitish grubs with brown heads,
and hinder portion of body thicker than fore end. When disturbed
grubs curl up. — White Grubs, p. 302.

3. Large dirty-brown maggots, ^-i inch long. — Meadow Maggots, p. 242.

Stems and Leaves:

(a) Young plants dwarfed, and color changed to yellow or brown; stems
shrivelled at the base, often bent or broken off; flaxseed objects found
embedded at or near the base. Oats immune. — Hessian Fly (Mayetiola
destructor), p. 245.

(b) Stems above last joint dead, and the heads white — "silver top" or "white
head" disease. Greenish maggot in stem above last joint. — Wheal Stem
Maggot {Meromyza americana) and American Frit-fly {Oscinis carbonaria),
pp. 260-1.

(c) Swellings or galls on the joints, and stems bent or broken before harvest. —
Joint Worm {Isosoma tritici), p. 354.

{d) Stems broken down and tunnelled, blackish near the joints; heads turning
white; presence in tunnel of yellowish-white larva of saw-fly; oats immune. —
Western Wheat-stem Saw-fly (Cephus occidentalis), p. 349.

(e) Leaves sickly and whitish; the presence of small red and larger black-
and-white bugs. — Chinch Bug (Blissus leticopterus), p. 161.

(/) Stems and leaves sickly; the presence of many green or yellowish-green
plant-lice. — Wheat Plant-louse {Aphis avence), English Grain Plant-louse
(Macrosiphum granarium) , p. 142.

(g) Stems and leaves eaten by large dingy striped caterpillars. — Army-worm
{Cirphis unipuncta), p. 190.

{h) Leaves eaten by locusts or grasshoppers. Red-legged and other Grass-
hoppers. — {Melanoplus femur-rubrum et al.), pp. 109-113.

71

72 ECONOMIC ENTOMOLOGY

Heads:

(a) Heads turn white and grains are shrivelled or imperfectly filled. — Wheat
Stem Maggot {Meromyza americana) and American Frit-fly {Oscinis car-
bonaria), p. 261.

(b) Heads shrivelled and blighted, and imperfectly filled; the presence of
orange-colored maggots. — Wheat Midge (Diplosis iritici), p. 249.

(c) Heads covered with green plant-lice. — Grain Louse {Aphis avetice), p. 142.

(d) Heads turn white; minute dots or lines on leaves usually run parallel
with the veins and remain white; the work of minute insects. — Grass Thrips
(Anaphothrips striatiis), p. 119.

(e) Spotting of the leaves, spots whitish at first, turning brown or black. —
Six-spotted Leaf-hopper {Cicadula 6-notata), p. 154.

(/■) Heads blasted and stems withered; the presence of frothy masses on the
stems. — Grass-feeding Froghop per {Philcenus lineatus), p. 153.

II. INSECTS INJURIOUS TO INDIAN CORN OR MAIZE

(Consult Bull. 44 Illinois Agric. Exper. Station)
Planted Seed:

(a) Plant fails to come up after planting; grain destroyed by a maggot which

eats out the interior. — Seed-corn Maggot {Phorbia fusciceps), p. 277.
{b) Plant fails to come up, or the young plant suddenly wilts after it is above
ground; the presence of hard, smooth, yellowish, wire-like worms. —
Wire-worms spp., p. 293.
Roots:

(a) Young plants killed or withered; roots eaten. — White Grubs or Wire-worms,

P- 303-

(b) Young plants unequal in growth; roots dwarfed without external injury;
presence of ants. — Corn-root Louse {Aphis maidi-radicis) .

Stalks:

{a) Plants cut off near surface of ground. — Cutworms, p. 185.
{b) Plants unthrifty and covered with greenish plant-lice. — Corn Plant-louse
{Aphis maidis), p. 142.

(c) Stalks punctured and slit. — Corn Bill Bugs {Sphenophorus spp.), p. 338.
{d) Pith of stalk and pedicel of cob tunneled by a flesh-colored caterpillar,

terminal internode broken. — European Corn Borer {Pyrausta nubilalis).
Leaves:

{a) Leaves thickly covered with green plant-lice. — Corn Plant-louse {Aphis
maidis).

{b) Leaves eaten. — Army-worm {Cirphis unipuncta) and Grasshopper, p. 190.

(c) Leaves perforated by round or oblong holes arranged in parallel trans-
verse rows. — Corn Bill Bugs, p. 338.

{d) Leaves wilted and brownish, sometimes sickly and whitish; the presence of
small red and larger black-and-white bugs. — Chinch Bug {Blissus leuco-
pterus), p. 161.

(e) Leaves wilted and brownish caused by the maggot of a syrphid fly. —
Corn-feeding Syrphid Fly {Mesogramma politus), p. 251.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 73

Ears:

(a) Developing kernels eaten; presence of much excrement. — Corn Ear Worm

(Heliothis ohsoleta), p. 195.
(i) Stalks of ears covered with plant-lice. — Corn Plant-louse {Aphis maidis),

p. 142.
(c) Developing kernels eaten; cob and tassel stalk tunneled. — European Corn
Borer {Pyrausta niihilalis), p. 212.

III. INSECTS INJURIOUS TO CLOVER AND ALFALFA

(Consult Bull. 134 Illinois Agric. Exper. Station, 1909)
Roots:

(a) Second year plants wilted and dead, breaking off easily at the crown.

Main root tunnelled and occupied by white footless grubs or little dark

brown cylindrical beetles. — Clover Root Borer (Hylastinus ohscurus), p. 341.

{b) Plants wilted and leaves dead, mealy bugs near crown of root. — Clover

Root Mealy Bugs (Pseudococcus trifolii), p. 133.

Stems:

(a) A long burrow with brown discolored walls in the pith of the stem which
falls to the ground prematurely. — Clover Stem Borer (Languria mozardi).

(b) Stems cut off or eaten. — Cutworms, Army-worms {Cirphis tinipuncta) and
Grasshoppers, p. 109.

(c) Stems and leaves withered and dead; plants covered with large green
long-legged plant -lice. — Pea or Clover Plant-louse (Macrosiphum pisi),

p. 149.
Leaves:

(a) Leaves fuU of round holes, and edges gnawed. — Clover Leaf Weevil (Phy-
tonomus punctatus), p. 331.

(b) Leaves eaten and with a ragged appearance. — Grasshoppers, p. 109.

(c) Leaves folded along midrib, yellowish or brownish, with white or orange
maggots or silken cocoons within the folds. — Clover Leaf Midge (Dasyneura
trifolii), p. 248.

Heads and Seed:

(a) Florets at blossoming-time green and undeveloped; the ovaries empty or
with an orange pink or whitish maggot. — Clover Seed Midge (Dasyneura
leguminicola), p. 246.
{b) Florets withered and seeds undeveloped; the presence of frothy masses on

stems. — Meadow Fro ghop per {Philanus spumarius), p. 153.
(c) Seeds eaten, becoming brown, brittle, and hollow; affected seeds dull brown
and often misshapen and of small size; maggot minute, white and footless. —
Clover Seed Chalcid (Bruchophagus funebris), p. 355.
{d) Unopened blossoms destroyed, a cavity eaten in the head. — Clover Seed
Caterpillar (Laspeyresia inter stitictana), p. 228.
Stacked or Stored Clover Hay:

(a) Hay containing white silky webs and particles of excrement. — Clover Hay-
worm (Hypsopygia costalis), p. 208.

74 ECONOMIC ENTOMOLOGY

IV. INSECTS INJURIOUS TO PEAS AND BEANS

Planted Seeds:

(a) Plant fails to come up, due to work of White Grubs or Wireworms, or Bean
or Seed Corn Maggot, p. 277.
Stalks and Leaves:

(a) Plants cut off at night near surface of the ground. — Cutworms, p. 185.

(b) Plants unhealthy, often killed by sucking lice. — Pea Louse {Macrosiphum
pisi), p. 149.

(c) Plants (beans) sickly and sooty, caused by a black aphis feeding at the tips
at blossoming time. — Bean Aphis {Aphis rumicis), p. 148.

Seeds:

(a) Seeds (peas) within the pod partly eaten and web-covered; pellets of excre-
ment about injured seed. — Pea Moth {Las peyresia nigricana), p. 226.

{b) Seeds within the pod (peas) perforated with holes; footless grubs within. —
Pea Weevil {Bruchus pisorum), p. 319.

(c) Seeds (Beans) perforated with (sometimes many) holes; footless grubs
within. — Bean Weevil {Bruchus obtectus), p. 319.

V. INSECTS INJURIOUS TO STORED GRAIN PRODUCTS

(After Girault, Bull. 156 Illinois Ag. Exp. St.)

Moths or Millers,
{a) Caterpillar small, whitish, living in grains of corn or wheat, pupating
within the grain, and emerging through a round hole covered with
silk at or near the tip of the kernel. Adult moths grayish clay-
yellow, small. — Angoumois Grain Moth {Sitotroga cerealella), p. 214.
{b) Caterpillars, spinning much silk, usually forming a silken tube to
which they retire; this tube covered with food particles. Living in
flour, meal, chaff, sometimes among grain, or in food substances.
Full-grown caterpillars make a cocoon.

1. Caterpillar free-living usually not concealed within a silken tube,
olive-green to pinkish, infesting grain or meal, webbing particles
together, covering bags of grain with a web of silk and generally
scattering silk in all directions. The moth is brown and gray.
Cocoon elliptical, slender, fragile and of clear silk. — Indian Meal
Moth {Plodia inter ptmctella) , p. 214.

2. Caterpillars living in densely woven silken cases covered with
particles of the food substance. Common in flour or chaff in
corners.

(i) A yellowish white to pinkish caterpillar in flour, webbing it
together and forming a cocoon covered with particles of
flour. Moth dark grayish. — Mediterranean Flour Moth
{Ephestia kuehniella), p. 213.

(2) A soiled grayish caterpillar, darker at each end, living
in chaff or other vegetable debris in dark damp places,

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 75

securely webbing the food substance together, so that
it becomes matted; larval case and cocoon completely
hidden, covered with the food substance. Adults very
beautiful and delicately colored moths. — Meal Snout Moth
{Pyralis farinalis), p. 208.

Beetles or Weevils.
(a) Small insects living in kernels of grain, or among grain and other
stored products.

1. A very small, fat, humped-backed grub, in kernels of wheat or
corn; yellowish- white, legless, and wrinkled, unable to crawl;
pupa within the kernel. Adult smaller than a grain of wheat,
with a snout, and elbowed feelers attached to the snout.

(i) Adult beetle chestnut-brown, without spots on its upper
wings. Slightly larger than the next, more common in the
North. — Granary or Black Weevil (Calandra granaria), p.
337-

(2) Adult beetle somewhat duller brown than the preceding
with four reddish spots, one on each outer corner of the
upper wing. A southern species. — Rice or Spotted Weevil
(Calandra oryza).

2. Small, more or less slender, somewhat flattened grubs, with dis-
tinct head and thoracic legs, crawling about in the debris of var-
ious grains or their products, or in vegetable foodstuffs.
Adults flattened, longer than wide, the head not prolonged into
a snout. They occur with the grubs, actively feeding.

(i) Grub uniform in color, whitish, about one-fourth inch
long, slender, its head narrower than the first body segment;
pupa with the thorax not toothed laterally, but with most of
the abdominal segments bearing a tooth-like lobe, acute at
each outer corner and toothed along its sides. Adult beetle
active, smooth, elliptical, and reddish brown. — Confused
Flour Beetle (Tribolium confusum), p. 328.

(2) Grub whitish, with a rectangular yellowish area on
each segment above, only the margin whitish as seen
from above; head broader than first body segment.
Pupa bears along each side of the thorax and abdomen
a series of stout lobe-like teeth, which are cylindrical-
rectangular and blunt. Adult beetle smaller than in the
preceding species, color dark chocolate-brown, sides
of the thorax saw-toothed.— 5flw-/oo//rc(/ Grain Beetle
(Silvanus surinamensis), p. 326.

(3) Grub dull white with a dark brown head; fleshy, three-
fourths inch long; posterior end with two dark horny
points. Pupa white, adult beetle, elongate, depressed.

76 ECONOMIC ENTOMOLOGY

nearly black, one-third inch long. — Cadelle (Tenebroides
mauritanicus) , p. 326.
(b) Large insects, concealed in the bottoms of bins, corners, and the like,
feeding upon flour, meal or bran. Adults large black beetles; the lar-
vas, large, cylindrical, wormlike creatures, resembling wireworms.

1. Adult not quite black in color, shining, its third antennal joint not
quite twice as long as the second; larva light yellowish, shining. —
Yellow Meal-worm Beetle {Tenebrio molitor ), p. 327.

2. Adult black and without luster, its third antennal joint thrice as
long as the second; larva very dark, shining. — Dark Meal-worm
Beetle {Tenebrio obsctiriis), p 328.

VI. INSECTS INJURIOUS TO ROOT CROPS

(Turnips, rape, mangels, and carrots)
(Consult Bull. 52 C E. P., Ottawa, and Bull. 60, 111. Exp. Sta.)
Roots:

(a) Tips of roots of young carrots with rusty patches on surface, or rust colored

tunnels in the pulp, due to slender yellowish- white maggots. — Carrot Rust

Fly {Psila rosce), p. 262.

(6) Roots of turnips bored or tunnelled by minute grubs or maggots. — Turnip

Flea Beetle (Phyllotreta vittata); Cabbage Root Maggot {Phorbia brassicce),

P- 273-
(c) Roots cut off. — Wireworms, White Grubs, Cutworms, pp. 185, 293, 302.

Stem and Leaves:

(a) Young plants cut off at the ground. — Cutworms, p. 185.

(b) Surface of first leaves of turnip and rape eaten into small holes by small
active black striped beetles. — Turnip Flea Beetle {Phyllotreta vittata), p. 314.

(c) Leaves partly consumed by pale-green caterpillars. — Cabbage Worm {Pieris
rapce), p. 175.

{d) Leaves eaten by caterpillars with black and yellow stripes. — Zebra Cater-
pillar {Ceramica picta), p. 188.

(e) Leaves wilt and turn yellow, with presence of greenish lice.- — Turnip Plant-
louse {Aphis brassica), p. 148.

(/) Young leaves eaten into holes and irregular blotches by small active green
caterpillars. — Diamond Back Moth {Plutella mactilipennis), p. 232.

(g) Under-surface of leaves covered with a very fine loose web; leaves yellow-
ish in patches, and minute red objects present. — Red Spiders, p. 367.

(A) Leaves eaten by red beetles with black stripes (Prairie Provinces). — Red
Turnip Beetle {Entomoscelis adonidis), p. 309.

VII. INSECTS INJURIOUS TO THE POTATO CROP

Tubers:

{a) Surface of tuber eaten and eyes sometimes destroyed so that growth does
not take place; or holes bored in the tuber. — White Grubs, Wireworms,
Millipedes, p. 369.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 77

Stalks and Leaves:

(a) Stalks cut off at the ground. — CiUworms, p. 185.

{b) Leaves eaten and infested with reddish soft grubs and striped beetles. —

Colorado Potato Beetle (Lepiinotarsa decemlineata) , p. 308.
(c) Leaves riddled with small holes or surface eaten in spots by small active

jumping black beetles. — Potato Flea Beetle (Epitrix cucumeris), p. 313.
{d) Leaves eaten and with a ragged appearance; presence of long black or

striped soft beetles. — Blister Beetles {Epicauta spp.), p. 325.
(e) Stalk wilts and dies, tunnel in stalk near the ground, and presence of a

white footless grub. — Potato Stalk Borer {Tricliobaris trinotata), p. 334.
if) Green plant-lice on the leaves; migrating to the rose. — Potato Plant-louse
{Macrosiphum solanifolice) .

VIII. INSECTS INJURIOUS TO GARDEN VEGETABLES

[Under the term "Garden Vegetables" may be included Asparagus, Beets,
Cabbage, Cauliflower, Celery, Cucumber, Onion, Parsnip. (Carrots, beans, peas
and potatoes have already been considered.)]

Roots:

(a) Roots of cabbage and cauliflower and bulb or base of onion mined by white

maggots. — Root Maggots (Phorbia brassicce and Phorbia cepetorum), p. 273.
{b) Roots of cucumber, squash, melon and pumpkin eaten, and plants fail to

come up. — White Grubs, Wireworms.
[c) Roots of cucumber, etc., gnawed and mined, plants wilt and die. — Striped

Cucumber Beetle {Diabrotica vittata), p. 307.

Stems and Leaves:

(a) Young plants cut off near surface of ground. — Cutivorms.

(b) Stalks, vines and leaves of cucumber, etc., eaten, and base, mined by small
white grubs. — Cucumber Beetles (Diabrotica spp.), p. 307.

(c) Vines of cucumber, etc., wilted, and presence of large dark stink-bugs on
leaves. — Squash Bug (Anasa tristis), p. 160.

(d) Leaves and vines of cucumber, etc., sickly and dirty, under surfaces infested
with greenish-black lice. — Melon Plant-louse {Aphis gossypii).

(e) Surface of leaves of cucumber, etc., eaten by small black beetles. — Cucumber
Flea Beetle (Epitrix cucumeris), p. 313.

(/) Leaves of cabbage, etc., ragged, eaten by pale-green caterpillars. — Cabbage

Worm (Pieris rapa), p. 175.
(g) Leaves of cabbage, etc., wilted, and under-surface covered with greenish

plant-lice. — Cabbage Plant-louse (Aphis brassicce), p. 148.

IX. INSECTS INJURIOUS TO THE APPLE

(Consult Manual of Fruit Insects by Slingerland and Crosby)
Roots:

(a^l Bluish-white mouldy lice causing knots or swellings on the smaller roots. —
Woolly Aphis (Schizoneura lanigera), p. 145.

78 ECONOMIC ENTOMOLOGY

(b) Large white grubs feeding on the roots of nursery stock. — White Grubs

{Lachnoslerna spp.), p. 302.
Trunk, Branches and Tmigs:

(a) A green curiously shaped bug producing longitudinal slits in the bark;

eggs laid under the edges of the slits. — Buffalo Tree Hopper {Ceresa hubalus),

P- 157-
{b) White woolly patches on the twigs which are usually scarred. — Woolly

Aphis {Schizoneura lanigera), p. 145.
(f) Green soft-bodied sucking insects in clusters on young growths, particularly

at ends of twigs, producing distortions. — Apple Aphids (Aphis mali, A.

sorbi and A. avencs), p. 143.
{d) Snout beetles gnawing off the bark in patches. — Imbricated Snout Beetle

{Epicarus imbricatus).
(e) Fixed to bark:

1. Scales round and gray and black producing an ashy gray incrusta-
I tion on the bark. — San Jose Scale (Aspidiotus perniciosus) , p. 126.

2. Bark rough with mussel-shaped scales. — Oystef-shell Scale (Lepido-
saphes ulmi), p. 124.

3. Bark scurfy with white scales. — Scurfy Scale (Chionaspis furfura),
p. 125.

(/) Making tunnels in the wood:

1. Large square-headed legless borer at or near the ground in tunnels,
with sawdust-like excrement. — Round-headed Borer (Saperda Candida),
p. 320.

2. Large flat-headed legless borer in upper trunk in tunnels with saw-
dust-like excrement. — Flat-headed Borer (Chrysobothris femorata),
p. 300.

3. Large grub in decaying wood. — Eyed Elater (Alaus ocidatus) and
Rough Osmoderma (Osmoderma scabra), p. 305.

4. Making tunnels between the bark and wood. Fruit Bark Beetle
{Eccoptogaster rugulosus), p. 339.

Buds:

(a) Light green caterpillars with brown head and shield, folding together the
opening leaves and feeding within. — Oblique Banded Leaf-roller (Cacoecia
rosaceana), Fruit-tree Leaf Roller (C. argyrospila), and Leaf Grumpier {Mineola
indigenella) , p. 230.

(b) Brownish caterpillar with black head and shield eating the centre of the
bud, or tunnelling it. — Eye-spotted Bud Moth {Tmetocera ocellana), p. 225.

(c) Measuring worms, eating leaves of buds. — Canker Worms (Alsophila pome-
taria and Paleacrita vernata), p. 205.

{d) Caterpillars feeding within pistol-shaped cases and eating irregular holes in
the bud leaves. — Pistol Case Bearer {Haploplilia malivorella), p. 235.

(ej Caterpillars feeding within cigar-shaped cases and eating small round holes
in the bud leaves. — Cigar Case Bearer (Haploptilia fletcherella), p. 234.

(/") Click beetles feeding on buds. — Corymbites spp., p. 297.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 79

Leaves:

(a) Gregarious caterpillars:

Caterpillars protected by webs:

1. Webs in forks of branches in spring. — Tent-caterpillar {Malacosoma
americana) , p. 203.

2. Webs covering the leaves in summer and early autumn. — Fall Weh
Worm (Hyphantria textor), p. 181.

3. Leaves partly eaten and drawn together by a web. — Palmer Worm
{Dichomeris pometella), p. 215.

Caterpillars not protected by a web:

1 . Clustered on limbs. — Yellow-necked Cater pillar{Datana ministra) , p . 1 98.

2. Red-humped Apple-tree Caterpillar {Schizura concinna), p. 199.

3. Forest Caterpillar {M. disstria), p. 204.
(6) Solitary caterpillars:

Protected caterpillars:

1. Mining within the leaf, pupa inside of folded leaf. — Apple Leaf Miner
{Tischeria malifoliella), p. 235.

2. Mining within the leaf, mature larva and pupa within a small oval
seed-like body. — Resplendent Shield Bearer (Aspidisca splendoriferella),
p. 232.

3. Feeding within a pistol-shaped case which stands out from the leaf. —
Pistol Case Bearer {Haploptilia malivorella) , p. 235.

4. Feeding within a cigar-shaped case which stands out from the leaf. —
Cigar Case Bearer {Haploptilia jletcherella), p. 234.

5. Feeding within a folded leaf. — Leaf Roller {Teras malivorana), Caccecia
spp., Apple Leaf Sewer (Ancylis nubeculana), p. 230.

6. Feeding within a tube of silk, open at both ends, on epidermis and
inner tissues, leaving the veinlets. — Bud Moth {Tmetocera ocellana),
p. 225.

7. Feeding on tissues of leaves beneath a silk web. — Apple Leaf-skele-
tonizer (Psorosina hammondi), p. 213.

8. Brown caterpillar feeding within a crooked black case and attached
to twigs in winter. — Leaf Crumpler (Mineola indigenella) , p. 213.

Unprotected caterpillars:

1. Measuring worms in spring, feeding in the daytime. — Canker Worms
{A. pometaria and P. vernata), p. 205.

2. Sleek i6-legged caterpillars, feeding at night. — Cutworms, p. 186.

3. Large green caterpillar, covered with spiny tubercles. — Cecropia
Moth {Samia cecropia), p. 180.

4. Large apple-green caterpillar with white oblique stripes on sides. —
Polyphemus Moth {Telea polyphemus), p. 180.

5. Hairy caterpillar with long black tufts over head and tail. — Tussock
Moth (Hemerocampa leucosligma) , p. 202.

6. Large green caterpillar with a reddish-brown horn at tail, and seven
oblique stripes on each side. — Apple Sphinx {Sphinx gordius), p. 178.

8o ECONOMIC ENTOMOLOGY

7. Small caterpillars with brown head and yellowish-green body, feeding

on leaves. — Apple-leaf Bucculatrix {Bucculatrix pomifoliella), p. 236.

(c) Plant-lice. Greenish or rosy colored sucking insects feeding on the under

sides of leaves, often distorting them. — Aphis mali, A. sorbi, and A. avencB,

P- 143-
(i"! Beetles:

1. Large brown beetles feeding at night on leaves. — May Beetles {Lach-
nosterna spp.), p. 302.

2. Small brown beetles, feeding at night. — Leaf Beetles, p. 301.

(e) Miles. Oval reddish-brown mites feeding on leaves causing them to become
blanched, yellow or sickly. — Clover Mite {Bryohia pratensis), p. 367.
Fruit:

(o) Boring tunnels through thefrtnt:

1. Tunnels made mostly about the core; made by a pinkish caterpillar
three-fourths inch long when full grown; brown excrement often visible
at opening at blossom end of apple. — Codling Moth {Carpocapsa
ponionella), p. 219.

2. Tunnels not so deep as in i, often blotched mines near the surface.
Made by caterpillars not so large as codling worms. — Lesser Apple
Worm {Laspeyresia prunivora), p. 227.

3. Tunnels irregular and numerous made by a maggot. — Apple Maggot
{Trypeta pomonella), p. 266.

(b) Puncturing the fruit:

1. Four-humped beetles puncturing the fruit and distorting it. — Apple
Curculio (Anthonomus quadrigibbus), Plum Curculio {Conotrachelus
nenuphar), p. 329.

2. Purplish spots about the circular scales. — San Josi Scale {Aspidiotus
perniciosus), p. 126.

3. Puncturing and deforming the fruit.- — Several species of Capsida
(False tarnished plant bug and the apple red bugs) ; and Syntomaspis
druparum (p. 165).

(c) Eating holes in the fruit:

1. Large light yellow or apple-green caterpillars with a narrow cream
colored stripe along middle of the back. — Green Fruit Worms {Grap-
tolitha spp.j, p. 197.

2. Yellowish hairy beetle one-half inch long. — Bumble Flower Beetle
{Euphoria inda), p. 305.

3. Green worm-like saw-fly larva hibernating in cavities scooped out of
apple. — Dock False Worm {Ametastegia glabrata), p. 347.

X. INSECTS INJURIOUS TO THE PLUM
Roots:

(a) Burrows made by a caterpillar about the crown of the roots, occasionally
in young trees. — Peach-tree Borer (Synanthedon exitiosa), p. 216.

Trunk, Branches and Twigs:

(a) Tunnels in the wood by flat-headed grubs; sawdust-like excrement at the
mouth of tunnels. — Flat-headed Borer {Chrysobothris femorata), p. 300.

IDENTIFICATION OP INSECTS INJURIOUS TO CROPS 8 1

(b) Tunnels in the bark by small legless grubs.— Fr«/; Bark-bcelle {Eccoplo-
gaster rugulosus), p. 339.

(c) Bases of buds perforated, bark becomes discolored, and leaves and fruit
wither. — Pear Blight Beetle {Anisandrus pyri), p. 340.

(d) Fixed to bark:

1. Flat or saddle-shaped, or hemispherical dark-brown scales; wintering
forins small and flattish. Large scales appear after mid-summer,
brittle, contain only a whitish dust or empty egg-shells. — Fruit
Lecanium {Lecanium corni), p. 129.

2. Ashy-gray appearance of bark of badly infested trees due to small
gray or black circular scales. — San Jose Scale {Aspidiotus perniciosus) ,
p. 126.

3. Mussel-shaped scales, with whitish eggs underneath in winter. —
Oyster Shell Scale (Lepidosaphes ulmi), p. 124.

4. Bark scurfy with scales with purplish eggs underneath in winter. —
Scurfy Scale {Chionaspis furfiira), p. 125.

(e) A grass green curiously shaped bug producing longitudinal slits and eventu -
ally oval-shaped scars on the back of the twigs. — Buffalo Tree-hopper {Ceresa
bubalus), p. 157.

Leaves:

(a) Feeding in Colonies.

1. Caterpillars protected by webs in the forks of branches. — American
Tent-caterpillar (Malacosoma americana), p. 203.

2. Caterpillars protected by webs covering the leaves. — Fall Web-worm
{Hyphantria textor), p. 181.

3. Not protected by webs; greenish lice with sucking mouths. — Plum-
leaf Aphis {Aphis prunifolii).

{b) Solitary.

1. Measuring worms, feeding in the day time in spring. — Canker Worms
(Alsophila pomelaria), p. 205.

2. Fat greasy caterpillars, feeding at night in spring. — Cutworms, p. 192.

3. Hairy caterpillars with long black plumes over head and tail. —
Tussock Moth {Hemerocanipa leucostigma), p. 202.

4. Large buzzing beetles. — June Beetles {Lachnosterna spp.), p. 302.

5. Large apple-green caterpillar, with a horn near the tail, and with seven
broad oblique white stripes along each side. — Plum-tree Sphinx
(Sphinx drupiferarum), p. 178.

Other larvae are occasionally found feeding on the leaves of plum. —
The Viceroy (Limenitis disippus), Polyphemus and Cecropia, p. 180.
Fruit:

(a) A snout-beetle puncturing and making a crescent-shaped slit in the skin of
the young fruit which soon drops. — Plum Curculio {Conotrachelus nenuphar),

P- 329-
(6) Making a round hole in the young fruit. — Plum Gouger [Coccotorus scutel-
laris).

82 ECONOMIC ENTOMOLOGY

(c) A medium sized beetle eating holes in the ripe fruit.- — Bumble Floiver-hcdle

{Euphoria itida), p. 305.
{d) A long-legged straw-colored beetle eating holes in the half-ripe fruit. — Rose

Chafer {M acrodactylus snhspinosus), p. 305.

XI. INSECTS INJURIOUS TO THE CHERRY

Rool:

(a) A thick whitish grub, with brown head and legs, feeding in decaying roots.
Beetle large with powerful mandibles. — Stag Beetle (Lucanus dama), p. 318.
{b) A large white fleshy grub, with reddish head, feeding in old roots.- — Rough
Osmoderma (Osmoderma scabra), p. 305.

Trunk, Branches and Twigs:

(a) A snout beetle gnawing the twigs and fruit. — Imbricated Snout Beetle

{Epiccerus imbricatus) .
{b) A small beetle boring in the branches just above a bud, and burrowing
downward. — Apple Twig Borer {Amphicerus bicaudatus), p. 327.

(c) A flattened grub tunneling in the bark and sap-wood; beetle bronzy metallic.
— Divaricated Buprestis {Dicerca divaricata).

(d) Large sucking insect with transparent wings, inflicting wounds on the
smaller limbs and depositing eggs therein in August and September. —
Dog-day Cicada {Cicada tibicen), p. 157.

(e) Small circular scales, black in winter, with a circular depression about a
central nipple. — San Jose Scale {Aspidiolus perniciosus), p. 126.

{{) Dirty nests inclosing a colony of yellow caterpillars one-half inch long at
end of twigs. — Cherry-tree Tortrix {Caccecia cerasivorana), p. 230.

Leaves:

(a) A small beetle feeding on the leaves of red cherry. — Cherry Leaf Beetle

{Galerucella clavicollis) , p. 311.
{b) A shiny, dark-green slug, one-half inch long, feeding on soft tissues, leaving

the veins. — Pear or Cherry Slug {Eriocampoides limacina), p. 348.
(c) Shining black plant-lice infesting the terminal twigs chiefly, which become

distorted and discolored. — Cherry Plant-louse {Myzus cerasi), p. 144.
{d) Large bluish-green caterpillar two inches long with blue warts on each

segment, and coral red ones on the third and fourth segments. — Promethea

Moth {Callosamia promethea), p. 180.
(e) Large pale-green spiny caterpillar, striped on each side with white and

lilac. — lo Moth {Hyperchiria lo), p. 180.
(/) Caterpillars in colonies protected by webs in forks of branches in spring.

— American Tetit-cater pillar {Malacosoma americana), and Forest Tent-
caterpillar {M. disstria) not in webs, p. 203.
{g) Caterpillars in colonies protected by webs covering the leaves in summer

and early autumn. — Fall Web Worm {Hyphantria textor), p. 181.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS S;^

Fruit:

(a) A crescent cut on the cherry; grub, white and footless, with a brownish

horny head, feeding within. — Flum Curculio {Conlrachelus nenuphar), p. 329.
(ft) Yellowish-white maggots feeding on the pulpy juices near the pit, inducing

a rotting. — Cherry Fruit Flies {Rhagolctis cingulata and R. fausta), p. 265.

XII. INSECTS INJURIOUS TO THE PEACH

Root and Loiver Trunk:

{a) Tunneling in the bark and sapwood of the root and lower trunk, causing an
exudation of gum, which is seen at base of tree mingled with the castings. —
Peach Tree Borer {Synanthedon exitiosa), p. 216.

Trunk and Branches:

(a) In early spring a minute caterpillar bores into the shodts of new leaves,

killing the growing terminals. — Peach Twig Borer {Anarsia lineatella),

p. 215.
{b) Black hemispherical scales attached to the bark. — Peach Leaf Lecanium

(Lecanium nigrofascialum) , p. 129.

(c) A beetle eating the buds and gnawing into the base of the twigs, causing
them to break and fall.- — New York Weevil {Ithycerus noveboracensis).

(d) Round scales, gray or black; twigs presenting a scurfy appearance. —
San Jose Scale (Aspidiotus perniciosiis) , p. 126.

(e) Oval scars and longitudinal slits on bark produced by a green buffalo-
shaped bug. — Buffalo Tree Hopper {Ceresa bubalus), p. 157.

Leaves:

(a) Plant-lice, living in colonies under the leaves, causing them to thicken

and curl. — Peach Tree Aphis (Myzus persicce), p. 144.
(6) Minute round scales located usually along the veins. — San Jose Scale

{Aspidiotus perniciosus), p. 126.
(c) Caterpillars protected."

1. In a tortuous tube. — Leaf Grumpier (Mineola indiginella), p. 213.

2. In folded leaves. — Oblique Banded Leaf Roller {Cacoecia rosaceana),
p. 230.

Fruit:

(a) Long-legged yellowish beetles eating holes in half-grown peaches. — Rose

Chafer (Macrodactylus subspinosus), p. 305.
{b) Large yellow hairy beetles eating holes in ripe peaches.- — Bumble Flower

Beetle (Euphoria inda), p. 305.
(c) Small snout-beetles making a puncture and crescent in the young fruit. —

Plum Curculio (Conotrachelus nenuphar), p. 329.

XIII. INSECTS INJURIOUS TO THE RASPBERRY AND BLACKBERRY

Roots and Base of Canes:

(a) Large grub over two inches long, boring large tunnels in the woody portion
of main root. The canes suddenly die. — Giant Root Borer {Prionus laticollis) ,
p. 321.

84 ECONOMIC ENTOMOLOGY

(/)) Canes at base of main root girdled by a yellowish- white caterpillar in late
summer and autumn. — Bramble Croiun Borer (Bembccia marginala), p. 218.
Canes:

(a) Longitudinal row of punctures on canes. — Black-horned Tree Cricket {QLcan-
thiis nigricornis), p. 116.

{b) Tips of raspberry canes wilting in early summer, due to a girdling of the
canes inside the bark. — Raspberry Cane Maggot {Phorhia rubivora), p. 277.

(c) Tips of shoots of raspberry wilting in July and August; two rows of hori-
zontal punctures one inch apart at base of wilted portion, with a small hole
between. Canes burrowed to the base before autumn. — Raspberry Cane
Borer (Oberea bimaculala), p. 321.

{d) Swellings on canes of raspberry and blackberry. — Red-necked Cane Borer
(Agrilus^ruficollis), p. 301.
Buds:

{a) A small snout-beetle puncturing the flower stem close to the buds, and
also the buds. — Strawberry Weevil {Anlhonomus signatus), p. 232.

{b) A small yellowish beetle eating the flower buds, which either fail to open or
wither. — Pale Brown Byturus {Bytiirus unicolor), p. 292.

(c) A small brownish caterpillar eating the opening buds. — Bud Moth (Tmeto-
cera ocellana), p. 225.
Leaves:

(a) Bugs sucking the sap of young growing parts, and arresting their develop-
ment. — Tarnished Plant Bug (Lygus pratensis), p. 163.

{p) Suckers and leaves curled up with enclosed lice. — Bramble Flea Louse
(Trioza tripunctata), p. 152.

(c) Small greenish larvae with spiny tubercles eating the leaves in spring. —
Raspberry Saw-Fly {Monophadnus rubi), p. 347.
Fruit:

(a) A looper feeding on fruit of raspberry and blackberry. — Raspberry Geometer
(Synchlora aerata).

XIV. INSECTS INJURIOUS TO THE GOOSEBERRY AND CURRANT

Canes:

(a) Tips of canes girdled and wilted; pith tunneled. — Currant Stem Girdler
{Janus integer), p. 345.

(b) Centre of cane tunneled by a white caterpillar. — Imported Currant Borer
{Synanthedon tipulijormis), p. 217.

(c) Small flat circular scales, black or gray, with a depressed ring about a
central nipple in black forms. — San Jose Scale {Aspidiotus perniciosus) ,
p. 126.

{d) Oval hemispherical scales. — Currant Lecanium {Lecanium ribis).
(e) Longitudinal rows of punctures on canes. — Black-horned Tree Cricket
{CEcanthus nigricornis), p. ii6.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 85

Leaves:

(a) Larvae, 20-Iegged, dull white when young, then greenish with black spots,

finally greenish yellow, eating holes in the leaves in early spring. — Imported

Currant Worm (Pteronus ribesii), p. 346.
{b) Leaves curled, blistered, and with a reddish appearance on upper surface,

caused by yellowish plant-lice — Currant Plant-louse {Myzus ribis), p. 145.
(c) Leaves turning brown and dying. — Four Lined Leaf-hug {Poecilocapsus

Uneatus), p. 163^
{d) Measuring worm feeding on leaves of gooseberry and black currant. —

Currant S pan-worm {Cymatophora ribearia), p. 206.
(e) White spots on leaves, produced by a pale green sucking insect occurring

on the under surface. — Currant Leaf Hopper {Empoasca), p. 155.
(/) Green plant-lice. — Green Gooseberry Aphis {Aphis sanborni).

Fruit:

(a) Greyish caterpillar boring into young fruit and eating out its contents. —
Gooseberry Fruit Worm {Zophodia grossularia).

(b) Purplish spots surrounding small circular scales. — San Jose Scale {Aspidiotus
perniciosus) y p. 126.

(c) Yellow oval maggots eating the gooseberry. — Gooseberry Midge (Cecido-
myia grossularia) .

(d) Small white maggot eating the currant and gooseberry, causing the fruit
to turn red and fall. — Currant Fruit-miner (Epochra canadensis), p. 265.

XV. INSECTS INJURIOUS TO THE GRAPE

(Consult Bull. 33i> N. Y. Ag. Exp. St. and Farmers' Bull. 70, U. S. Dep. Ag.)

Roots:

(a) Producing soft yellow irregular spherical galls on rootlets and larger roots,
causing death. — Grape Vine Phylloxera (Phylloxera vasfatrix), p. 148.

(b) Large borer, cutting a tube through the root near the surface. — Broad-
necked Prionus (Priontis laticollis).

(c) Grub eating the bark of both the large and small roots. — Grape Vine Fidia
(Fidia viticida), p. 311.

Branches:

{a) Young shoots suddenly break off or droop in spring; a small hole just above
the base of the shoot leading into a burrow. — Apple Twig Borer (Amphicerus
bicaudatus), p. 327.

(b) Canes show roughened longitudinal rows of perforations in the bark. —
Tree Cricket ((Ecanthus nigricornis), p. 116.

(c) Canes exhibiting white cottony masses attached to a reddish-brown scale. —
Cottony Scale {Pulvinaria vitis), p. 130.

Leaves:

{a) Leaves riddled with irregular holes about mid-summer by a little beetle. —
Grape V tne Fidia {Fidia viticida), p. 311.

86 ECONOMIC ENTOMOLOGY

(b) Small, shining, blue beetle boring into buds in spring, also eating small
holes in expanding leaves. — Grape Vine Flea Beetle {Haltica chalybea),p. 315.

(c) Long-legged brownish beetles eating the blossoms, leaves and fruit. —
Rose Chafer (Macrodactylus suhspinosus), p. 305.

{d) Greenish caterpillar, feeding within a folded leaf and skeletonizing it, about

mid-summer. — Grape Leaf Folder (Desmia funeralis).
(e) Leaves blotched and scorched, finally curling up and falling, caused by

little jumping insects. — Grape Thrips or Leaf Hopper {Typhlocyba comes),

P- 155-
(/) Large greenish caterpillar, with a pale yellow stripe down each side and a

horn near tail. — Grape Vine Sphinx {Ampelceca myron), p. 178.
ig) Several other sphingid larvas feed on the leaves of the grape.
{h) Black beetle eating the tissues on the upper surface of the leaves, and

discoloring them. — Red-headed Sysiena {Systena frontalis), p. 315.
(?) Producing small, irregular, spherical galls on the lower surface of the leaves.

— Grape Vine Phylloxera (Phylloxera vastatrix), p. 148.
(j) Large reddish-yellow beetle with six black spots on wing cover, eating holes

in leaves. — Spotted Pelidnota (Pelidnota punctata), p. 302.
Fruit:

(a) Ripening fruit discolored and burrowed by a whitish caterpillar. — Grape

Berry Moth [Polychrosis viteana), p. 228.
(6) Holes eaten in ripe fruit; beetle large, yellowish, hairy. — Bumble Flower

Beetle (Euphoria inda), p. 305.
(c) Holes eaten in young fruit by a long-legged beetle. — Rose Chafer (Macro-
dactylus subspinosus], p. 305.

XVI. INSECTS INJURIOUS TO THE STRAWBERRY

Roots :

(a) A pinkish caterpillar boring irregular channels through the crown and
larger roots, causing them to wither and die. — Strawberry Root Borer
(Anarsia lineatella), p. 215.

(b) A white grub boring downward from the crown. — Strawberry Crown Borer
(Tyloderma fragarice), p. 332.

(c) A large white grub eating the roots. — May Beetle (Lachnosterna sp.), p. 302.

(d) Grubs girdling the roots, causing death. — Strawberry Root-weevil (Otio-
rhynchus ovatus), p. 336.

Leaves:

(a) Brownish caterpillars, in June and August, rolling the leaves into cases and
fastening them with silk. — Strawberry Leaf Roller (Ancylus comptana),
p. 232.

(b) Young plants gnawed off at the surface. — Cutworms, p. 185.

(c) Small pale spotted active beetles riddling the leaves with holes in June. —
Spotted Paria (Paria 6-notala).

(d) Small active jumping striped beetles, eating holes in the leaves. — Striped
Flea Beetle (Phyllotrela vittata), p. 314.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 87

(e) Twenty-legged grubs eating holes in the leaves. — Strawberry Saw fly
{Entphytiis maculatus)
Fruit:

(a) Caterpillars feeding on the berry. — Stalk Borer (Papcipertia nitela), p. 196.

(b) Minute black bugs producing a buggy odor when eaten with berry. — Flea-
like Negro Bug {Corimelana pulicaria), p. 167.

(c) Flower buds drooping and bending over. — Strawberry Weevil (Anthonomus
signatus), p. 332-

(d) Fruits deformed to "buttons. " — Strawberry Thrips (Euthrips Irilici), p. 122.

XVII. INSECTS AFFECTING SHADE TREES

(Consult Insects Affecting Park and Woodland Trees by Felt)

(a) Feeding on the leaves.

(b) Feeding or resting under webbed tents.

(i) Hairy yellowish-brown and black marked caterpillars feeding
on leaves within webbed tents in July-Sept.; adult moths white
or black-spotted. — Fall Web Worm {Hyphantria cimca), p. 181.
(2) Hairy black caterpillars, white stripe along middle of back, lateral
white and yellow line with blue spots. Resting in silken webbed
tents at angles of branches. — Orchard Tent-caterpillar {Malacosoma
americana), p. 203.
^bb) Feeding free on the leaves.
I. Adult mothsnot white.

(i) Caterpillars with a broken line of white dots along back,
and resting in masses on sides of branches and trunks, not
within webs. — Forest Tent-caterpillar {Malacosoma disstria),
p. 204.

(2) Caterpillars with red heads and yellow and black tufts and
pencils. Female moth wingless. — White-marked Tussock Moth
{H enter ocani pa leucostigma), p. 202.

(3) Brownish caterpillars with blue and reddish warts; hibernat-
ing as egg-masses covered with hair; adult female moth with
white wings marked with dark wavy lines, wings of males
light brown. — Gipsy Moth {Porthetria dispar), p. 200.

(4) "Measuring worms" feeding in the daytime in spring and
early summer. — Fall Canker Worm {Alsophila pometaria),
p. 205.

(5) Caterpillars with tufts of white, black, or yellow hairs, and
pencils of black or orange or white hairs. Feeding on hickory,
butternut, etc. — Tiger Moths (Halisidota spp.), p. 183.

(6) Caterpillars with sharp pale yellow hairs and with a pair
of long black hair pencils on the first and third abdominal
segments, and a single one on the eighth. Feeding on elm,
maple, hickory, oak, ash, poplar, etc. — American Dagger Moth
{Acronycta americana), p. 198.

58 ECONOMIC ENTOMOLOGY

(7) Caterpillars black with a loose covering of soft whitish hairs.
Feeding in clusters on walnut, hickory, oak, beech, etc. —
Walnut Caterpillar {Datana integerrima), p. 199.

(8) Small green caterpillars, skeletonizing the leaves of birches
and forming small round white moulting cocoons on the
twigs and leaves. — Birch Leaf Skeletonizer {Bucculatrix
canadensisella), p. 236.

(9) A bright yellow looper with rust-colored head and with ten
crinkled black lines along the back. Attacks elm, basswood,
hickory, apple, etc. — Lime-tree Winter Moth (Erannis liliaria).

2. Adult moths white.

(i) Caterpillars reddish-black with only two pairs of prolegs;
with three pairs of small tubercles on back; hibernate as egg-
masses of 20-100 on branches. — Snow-white Linden Moth
{Ennomos subsigniarius), p. 206.

(2) Dark brown caterpillars, with a lateral row of white hairs
and bright red tubercles on sixth and seventh adbominal seg-
ments; hibernate as one-fourth grown caterpillars in nests of
webbed leaves on tips of trees; adult moth with a tuft of
brown hairs at tip of abdomen. — Brown Tail Moth {Euproctis
chrysorrhcea), p. 200.

3. Adults are butterflies. Caterpillars large, black, red-marked and
spiny, feeding in clusters on terminal branches of elm, willow,
poplsiT.— Spiny Elm Caterpillar {Aglais antiopa). p 176.

4. Adults are beetles. Adults eating irregular circular holes in elm
leaves and grubs skeletonizing the under surface. — Elm Leaf Beetle
(Galerucella luteola), p. 309.

5. Adults are Saw-flies.

(i) Larvae cylindric, coiled, yellowish-white, with a black line
down the middle of back, feeding on elm, poplar, willow, etc. —
Elm Saw-fly {Cimhex amcricana), p. 347.

(2) Larvae with jet black head and green body, each segment
except second marked with double parallel rows of dark
dots; feeding on larch leaves. — Larch Saw-fly (LygcBonematus
erichsonii), p. 346.

(aa) Boring in trunks and branches.
(b) Adults are moths.

1. Whitish caterpillars with distinct spots and tubercles making
burrows in twigs and larger branches, which often die and project
above leafy branches. Moths are white with blue and black
markings. — Leopard Moth {Zeuzera pyrina), p. 237.

2. Large white or reddish- white caterpillars making large round
irregular borings in oak, maple and locust. Moth is large, dark
grey. — Carpenter Worm {Prionoxystus robinia), p. 238.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 89

(bb) Adults are beetles.

1. Long-horned or cerambycid beetles.

(i) Large fleshy legless grubs making broad shallow tunnels in
sapwood of sugar-maples, often killing limbs. Adult beetle
brilliantly marked with yellow and black. — Sugar Maple
Borer {Plagionotiis speciosus), p. 323.

(2) A whitish hairy grub making a central burrow plugged with
sawdust, and cutting off twigs of maple or oak. — Tivig Primer
(Elaphidion villosum), p. 323.

(3) White flattened legless grubs working under the bark of elm;
adult a gray beetle with red lines and black spots. — Elm Borer
(Saperda tridentata), p. 321.

(4) White legless grubs making large irregular channels in sap-
wood and inner bark of poplar; large blackened swollen scars
on the surface of the trunk and limbs of affected trees. —
Poplar Borer {Saperda calcarata) tunnels in poplar producing
rough discolored scars on the trunk. Saperda Candida bores
into hawthorn, mountain ash, and fruit trees, and Saperda
veslita into basswood.

(s) Club-shaped grubs, making irregular ugly scars opening
into burrows in black locust. Adult beetle is dull black
brightly marked with golden yellow, and feeds on golden rod
blossoms. — Locust Borer (Cyllene robinice), p. 321,

2. Metallic wood borers or Buprestid beetles.

(i) Large headed flattened legless grubs making shallow tunnels. —
Flat-headed Borer (Chrysobothris femorata), p. 300.

(2) A flattened whitish grub with a large flattened head, making
irregular spiral burrows in the inner bark of birch. — Bronze
Birch Borer {Agrilus anxhis), p, 301.

{aaa) Sucking the juices from twigs or leaves.
ib) On the leaves.

1. Producing terminal galls on white and Norway spruce; branch
scraggly deformed. — Spruce Gall Aphis {Chermes similis), p. 150.

2. Producing galls on white and Norway spruce, not terminal, pine-
apple shaped. — Spruce Gall Aphis (Chermes abietis), p. 149.

3. Snow-white woolly plant-lice on leaves of larch. — Larch Woolly
Aphis {Chermes strobilobius).

[bb) On the bark.

1. Clusters of woolly aphis on elm. — Woolly Aphis of Elm {Schizoneura
americana), p. 145.

2. Reddish woolly bordered bark-lice on under surface of elm leaves. —
Elm Bark-louse (Gossyparia spuria), p. 130.

3. Cottony masses attached to brown scales on under side of twigs
of soft maple, elms, etc. — Cottony Maple Scale {Pulvinaria vilis),
p. 130.

90 ECONOMIC ENTOMOLOGY

4. Hemispherical reddish scales mottled with black lines on under
side of branches of maples. — Terrapin Scale (Lecanium nigrofas-
cialum), p. 129.

5. Flocculent white masses upon greenbark of cultivated white pine. —
Pine Bark Aphis (Chermes pinicorticis), p. 150.

6. Twigs of balsam twisted and leaves curled by plant-lice. — Balsam
Twig Aphis {Mindarits abietinus).

XVIII. INSECTS INJURIOUS TO GREENHOUSE PLANTS

(a) Minute active white four-winged flies living on the under side of leaves,
sucking the juices; young are oval, flat and greenish. — White Fly (Aleyrodes vapor-
ariorum), p. 151.

(6) Small soft mealy-covered bugs, with eggs enclosed in cottony sacks. — Mealy
Bugs (Pseudococcus spp.), p. 131.

(c) Oval, flat or saddle-shaped scales, on leaves of lemons, ferns, oleanders,
crotons, etc. — Soft Scale (Lecanium hemisphericum), p. 134.

{d) Round scales on leaves and twigs of ivy, date palms, etc. — Hard Scale
{Aspidiotus spp.), p. 134.

(e) White scales on leaves of Boston fern, aspidistra, etc., causing spotting and
browning. — Aspidistra Scale {Hemichionaspis aspidistrcB), p. 135.

(/) Green plant-lice, often infesting violets and sucking the juices from the
leaves, checking the growth. — Green Aphis (Myzus persicce), p. 144.

(g) Black plant-lice sucking the juices of chrysanthemums. — Black Aphis (Macro-
siphum sanborni), p. 149.

(A) Red mites, spinning fine webs on under surface of leaves and sucking the
juices rendering the leaves sickly yellow.— i?e^ Spider (Tetranychus bimaculatus).

(i) A small maggot, causing the edges of violet leaves to curl and turn yellow. —
Violet Gall-fly (Diplosis violicola).

(j) A small greenish-white and striped caterpillar, eating lower epidermis of
chrysanthemums, cinerarias, roses, carnations, etc., and tying the leaves together. —
Greenhouse Leaf-tyer (Phlyctcenia ferrugalis), p. 210.

(k) Maggots feeding in flower and leaf buds of greenhouse roses, causing them to
brown, blacken and die. — Rose Midge (Dasyneura rhodophaga), p. 248.

(/) Flesh-colored legless grubs attacking roots of cyclamen, gloxinia, primula. —
Cyclameti Borer {Otiorhynchus sidcatus), p. 336.

XIX. INSECTS AFFECTING DOMESTIC ANIMALS

(Consult Insects Affecting Domestic Animals by Osborn, Bull. 5, U. S. Div. Ent.)

A. Sheep

(a) Maggots in nostrils and in nasal sinuses, causing catarrh and staggers;
deposited by a two-winged fly in June and July. — Sheep Bot-fly (CEstrus ovis).

(b) Wool falls off in patches and large scabs form on body with much itching due
to a mite. — Sheep Scab {Psoroples communis), p. 366.

IDENTIFICATION OF INSECTS INJURIOUS TO CROPS 91

(c) Brownish flattened tick-like insects sucking the blood; common on lambs in
spring. — Sheep Tick (Melophagiis ovinus), p. 279.

B. Cattle

(a) Swellings or "warbles" along the back in winter; bee-like flies bothering
cattle in June and July. — Ox-warble {Hypoderma linealum and H. bovts), p. 255.

(b) Small flies clustering on base of horns, flanks and belly of cattle in summer,
causing them much annoyance. — Horn Fly {Hcemalobia scrrata), p. 272.

(c) Slaty-colored sucking lice, often abundant on neck and shoulders of neglected
cattle. — Short-nosed Ox Louse {Hcematopinus etiryslernus), p. 000. Long-nosed Ox
Louse {Hamatoplnus vituli), p. i6g.

(d) "Little red lice" feeding on the rough parts of the skin and on the hairs,
causing irritation; most abundant in spring. — Biting Cattle Louse (Trichodectes
scalaris), p. 100.

(e) Hair falls off in patches and large scabs form — with much itching^due to
mites. Common Cattle Scab Mites (Psoroptes Communis bovis), Sarcoptic Scab Mite
(Sarcoptes scabiei bovis), Tail Mange Mite (Chorioptes bovis bovis). (See Farmers'
Bull. 1017, U. S. Dep. Ag.).

C. Horses

(a) Bots attached to wall of stomach — adult fly light brown; does not bite
but horse is worried; eggs laid on hairs of legs and shoulders. — Horse Bot-fly (Gastro-
philus intestinalis) , p. 258.

(b) Similar to (a) but eggs are attached to hairs of lips and nostrils. — Chin
Bot-fly (Gastrophilus nasalis) and the Red-tailed Bot-fly (G. hcemorrhoidalis) , p. 259.

(c) Large black fly that flies swiftly and bites severely, giving much annoyance
to horses. — Horse Gadfly (Tabanus atratus), p. 252.

D. Hogs

(a) Gray sucking lice, often quite large. — Hog Louse (Hmnatopinus urius), p.
169.

E. Poultry

(a) Yellowish or reddish mites infesting hens and chicks at night; piercing the
skin and sucking the blood, causing much irritation and often death. — Chicken Mite
(Dermanyssus gallincB), p. 364.

{b) Small pale yellow active insects feeding on rough parts of skin and bases
of hairs and feathers, causing much irritation. — Common Hen Louse (Menopon
pallidum), p. 100.

(c) Minute mites burrowing under the scales of foot, leg, comb and beak, pro-
ducing "scaly leg" with much irritation. Contagious. — Itch Mite (Sarcoptes
mutans), p. 365.

(d) Small mites causing the feathers to break off. Contagious. — Depluming
mite {Sarcoptes gallince).

92 ECONOMIC ENTOMOLOGY

XX. INSECTS OF THE HOUSEHOLD

A. Annoying the Inmates

(a) Slender two-winged insects; only the females bite or pierce the skin; larvae
and pupae live in stagnant water. — Common Mosquito {Ctilex pipiens), p. 243.

(b) Similar to (a) but larger and with wings spotted. — M alarial M osqiiito {Ano-
pheles maculi pennis) , p. 244.

(c) Two- winged insects, with four black lines on thorax; they lap but do not
pierce; eggs laid on manure or decaying organic matter. — House Fly {Musca do-
meslica), p. 270.

{d) Similar to (c) but with six black lines on thorax, and with piercing mouth-
parts. — Stable Fly (Stomoxys calcitrans), p. 271.

(e) Compressed, wingless long-legged insects with piercing and sucking mouth-
parts, hiding in bedding and clothing; eggs laid among hairs of cat or dog. — Cat
and Dog Flea {Pulex serraticeps), p. 280.

(/) Reddish-brown, flat bugs with buggy odor, hiding in day time in cracks, but
active at night; with piercing and sucking mouth-parts. — Bed-bugs (Cimex Icclu-
larius), p. 167.

B. Feeding on or Destroying Clothing, Carpets, Upholstery, Etc.

{a) Tiny dusky moths, laying eggs in furs or woolens, the larvae eating holes in
them. — Case-making Clothes Moth {Tinea pellionella), p. 236. Webbing Clothes Moth
{Tinea biselliella) , p. 237. Tapestry Clothes Moth {Trichophaga tapetzella), p. 237.

{b) Small oval red, black and white beetles, whose grubs are hairy, feeding on
carpets on underside, usually along a crack of the floor. — Buffalo Carpet Beetle
{Anthrenus scrophularice), p. 291.

(c) Tiny active wingless insects with silvery appearance, and with three long
feelers at hind end of body, feeding on linen or paper containing starch, sugar, etc.
Silver-fish {Lepisma saccharina), p. 95.

C. Feeding on Food Products

{a) Active wary light-brown insects with a "roachy" odor, found in pantries
and bakeries; several species but the most common is the Croton-bug or German
Cockroach {Ectobia germanica), p. 105.

{b) Brown beetles, one-third inch long, whose grubs are brown above, white below
and covered with long brown hairs; found where meats, skins and feathers are
kept. — Larder Beetle {Dermestes lardarius), p. 291.

(c) Large black flies with bluish abdomen and with black spines on thorax;
eggs laid on meat. — Blow or Meat Fly {Calliphora vomitoria), p. 273.

{d) Little red ants that have their nests in the wall or beneath the flooring. —
House Ants {Monomorinm pharaonis), p. 361.

(e) Black ants and pavement ants living outdoors sometimes invade houses. —
Black Ants {Monomorium minutiim), p. 361.

PART

CLASSIFICATION AND DESCRIPTION OF COMMON
INSECTS

THE COMMON ORDERS AND GROUPS OF INSECTS

SYNOPSIS OF THE ORDERS OF INSECTS REFERRED TO IN THE CLASS

BOOK

Aptera Group.

I. Thysanura.
II. Collembola.

Netiropteroida Group.

Orthopteroida Group.

Hemipteroida Group

Dipteroida Group.

I

III. Plecoptera.

IV. Ephemerida.
V. Odonata.

VI. Neuroptera.
VII. Mecoptera.
VIII. Trichoptera.

IX. Mallophaga.

X. Isoptera.

XL Corrodentia.

XII. Blattoidea.

XIII. Mantoidea.

XIV. Phasmoidea.
XV. Dermaptera.

XVI. Orthoptera.
XVII. Thysanoptera.

XVIII. Homoptera.
XIX. Hemiptera.
XX. Siphunculata.
XXI. Lepidoptera.
XXII. Coleoptera.
XXIIL Diptera.
XXIV. Siphonaptera.
XXV. Hymenoptera.

A. With two wings; mouth-parts formed for sucking or piercing; metamor-
phosis complete.^ — DIPTERA (Flies).

93

94 ECONOMIC ENTOMOLOGY

AA. With four wings.

B. Mouth-parts formed for biting.

C. Upper wings horny; metamorphosis complete. — COLEOPj'^j^ji
(Beetles), p. 280.
CC. Upper wings parchment-like; lower wings folded under the
upper; metamorphosis incomplete. — ORTHOPTeROIDA
Group (Locusts, etc.), p. 102.
CCC. Upper wings membranous with many veins. — NEUROP-
TEROIDA Group (Nerve-winged insects), p. 96.
BB. Mouth-parts formed for sucking and biting; wings with few cross veins
and similar in texture; metamorphosis complete. — HYMENOP-
TERA (Bees, etc.), p. 343.
BBB. Mouth-parts formed for sucking; wings covered with scales; metamor-
phosis cora^\tie.—LEPI DOPTERA (Butterflies and moths), p. 169.
BBBB. Mouth-parts formed for piercing.

C. Beak jointed; palpi absent; last joint of tarsi not bladder-like.
D. Wings of uniform texture; beak arising from the hinder
edge of under side of the head; metamorphosis incomplete.
—HOMOPTERA, p. 122.
DD. Fore wings leathery at base, membranous at tip; beak
arising from the front of the head; metamorphosis incom-
plete.— Z^£M/Pr£i?J (True Bugs), p. 158.
CC. Beak unjoin ted, palpi present; last joint of tarsi bladder-like,
and without claws; wings similar; metamorphosis incomplete. —
THYSANOPTERA (Thrips), p. 118.
AAA. Wingless.

B. Mouth-parts formed for biting; louse-like insects.

C. Mouth-parts retracted within the head; no metamorphosis. —
APTERA Group, p. 94.
CC. Mouth-parts not retracted within the head.

D. Antennas with many segments; metamorphosis incomplete.
—CORRODENTIA (Book-lice), p. 103.
DD. Antennas with not more than five segments; metamorpho-
sis incomplete. — MALLOPHAGA (Biting-lice), p. 100.
BB. Mouth-parts formed for sucking.

C. Tarsus with a single hook-like claw; with a fleshy unjointed
beak; parasitic on mammals (Parasitica). — SIPHUNCULATA,
p. 167
CC. Tarsus five-jointed; body compressed; metamorphosis complete. —
SIPHONAPTERA (Fleas).

The Aptera Group
Chief Orders and Families:

A. Abdomen with at least 10 segments; antennae many-jointed; usually with
terminal abdominal appendages. — Thysanura Order.
B. Body covered with scales. — Lepismidce.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS

95

BB. Body not covered with scales.

C. Caudal appendages many-jointed. — Campodcidce.
CC. Caudal appendages sickle-shaped. — Japygidce.
AA. Abdomen with not more than six segments; antennae with not more than
eight joints; no caudal appendages. — Collembola Order.
B. Ventral spring present.

C. Spring on penultimate abdominal segment.
D. Abdomen globular. — Sminthuridce.
DD Abdomen cylindrical. — Enlomobryidce.
CC. Spring on antepenult abdominal segment. — Podurida.
BB. Ventral spring absent. — Aphorurida.
Of the above Apterous families only one, the LepismidcB of the Thysanura,
contains forms that are of economic importance.

ORDER THYSANURA
LEPISMIDiE (Fish-moths)

The Fish-moth, Silver Fish, or "SUcker"

Linn.) sometimes does injury to books,
papers, labels and starched clothing. It
shuns light and is quite active.

Adult. — A minute, glistening, scaly, fish-
like active insect, wingless, 3^^ inch long,
body tapering to hind end where are three
long, bristle-shaped appendages; antennae
prominent; coxae strongly developed; biting
mouth parts.

Another species, Lepismadomestica Pack.,
is found in bakeries and mills in some locali-
ties. It has dusty markings on its upper
surface and is 3-^ inch long.

Control. — Frequent use of fresh insect
powder, sodium fluoride, or a poison-bait
of sweetened gluey paste and white arsenic
on bits of cardboard.

{Lepisma saccharina

PODURID^ (Springtails)

IT

Fig. 50.— The silver fish
{Lepisma saccharina) . {After
Marlatt.)

Two species may be noted in passing:
Achorutes armatum sometimes attacking seedlings causing disfigure-
ment and loss, and A. nivicola often abundant in maple sap in early
spring. Both species are minute, and have some of the habits of
flea-beetles (Fig, 51).

96

ECONOMIC ENTOMOLOGY

The Neuropteroida Group

Certain orders of aquatic insects have a superficial resemblance
of wing venation, and were formerly grouped together into one order,
the Neuroptera. Of the six main Orders
three have incomplete metamorphosis, viz.,
Plecoptera, Ephemerida and Odonata, and
three complete metamorphosis, viz., Tri-
choptera, Neuroptera and Mecoptera.

It is probable, therefore, that the first
three orders are not so highly evolved as the
last three. The former are lower than the
Orthoptera, while the latter are higher and
come between the Hemiptera and the
Lepidoptera.

Chief Orders: ^

The Neuropteroida (or nerve-winged) group of
insects includes six main orders which may be sepa-
rated as follows:

A. Lower wings folded in plaits under the
upper.
B. Wings covered with hairs; tarsi
5-jointed ; metamorphosis complete. —
Trichoptera (Caddice-fiies) .
BB. Wings not covered with hairs.
C. Tarsi 5-jointed; wings equal and with many veins and cross-veins;
mouth-parts well developed; metamorphosis complete. — Neurop-
tera (Dobson flies, Aphis lions, etc.).
CC. Tarsi 3-jointed; hind wings larger than fore-wings; with caudal
filaments; biting mouth-parts poorly developed; metamorphosis
incomplete.- — Plecoptera (Stone-flies) (Fig. 54).
AA. Lower wings not folded under the upper.

B. Head prolonged into a beak; antennae long; metamorphosis com-
plete. — Mecoptera (Scorpion-flies) .
BB. Head not prolonged into a beak; antennae inconspicuous; metamor-
phosis incomplete.

1 Handlirsch arranges these orders into groups as follows:

Odonata Sub-class Libelluloidea.

Plecoptera (Ephemerida) Sub-class Ephemeroidea.

Plecoptera Sub-class Perloidea.

Neuroptera |

Megaloptera [ Sub-class Neuropteroidea.

Raphidioidea J
Panorpatae )

Trichoptera [ Sub-class Panorpoidea.

Lepidoptera

Fig. si. — The snow
flea {A chorules nivi-
cola). Enlarged greatly.
{After Folsom.)

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS

97

C. Abdomen with 2 or 3 long filaments; lower wings much smaller
than upper; antennae short.^ — Ephcmcrida (May-flies) (Fig. 53)..
CC. Abdomen without jointed filaments; wings about equal in size;
antennas short. Odonata (Dragon-flies).

The larvae of most of the Neuropteroid insects are aquatic and are of little
economic importance in agriculture. They are of importance, however, in fish-
culture. In the Stone-flies Newcomer has recently reported that several species of
Taniopteryx (especially T. pacifica) with well developed mouth-parts cause consider-
able injury to foliage and fruit in Central Washington.

Fig. 52.-

-M ay-fly {Hexagenia), adult.
{After Folsom.)

Fig. 53. — May-fly, nymph.

LARVAL FORMS OF THE NEUROPTEROIDA

A. Body cylindrical, caterpillar-like. — Mecoptera.
AA. Body more or less depressed, not caterpillar-like.

B. Mandibles united with corresponding maxiUte. — Netiroptera.
BB. Mandibles separate from corresponding maxillae.

C. Body encased in a shell of gravel, etc. — Trichoptera.
CC. Body not encased in a shell.

D. Abdomen with external lateral gills and terminated by 2 or
3 long gill processes. — Ephemerida (Fig. 53).
7

98 ECONOMIC ENTOMOLOGY

DD. Abdomen without external lateral gills.

E. X-ower lip strong extensile and furnished with a pair of
opposable hooks; abdomen terminated by 3 leaf-like
tracheal gills, or with 5 spine-like appendages. —
Odonata.
EE. Lower lip not extensile and without hooks; caudal
filaments and antennae long and slender; thorax with
3 pairs of tracheal giWs.—Plecoptera.

On account, however, of their common occurrence the economic
entomologist should know a little at least regarding their habits and
life-history.

Stone-flies (Plecoptera). — The nymphs hve under stones in swift
streams, are flattish, and have tracheal gills, long legs, cerci and

Fig. 54.

-An adult stone-fly {Pteronarcys regalis).
Folsom).

Slightly reduced. {After

antennae. The adults are greyish and have prominent wings. The
hind wings are the larger and when at rest are folded under the front
ones. The larvae furnish food for fishes (Figs. 54 and 55).

May-flies (Ephemerida). — May-flies are well-known insects, being
attracted to lights in immense numbers in early summer. They have
large delicate wings and 2 or 3 long caudal filaments. The fore wings
are much larger than the hind ones. The nymphs Hve at the bottoms of
bodies of water, and have long legs, caudal filaments and prominent
tracheal gills. They_mature in i to 3 years, and furnish abundant
food for fishes.

CLASSIFICATION AND DESCEIPTION OF COMMON INSECTS

99

Dragon-flies and Damsel-flies (Odonataj.- — These insects are also
well known. They are rapid fliers over bodies of water, feeding on
flies and mosquitoes. The nymphs live at the
bottom of ponds and streams. They have
long legs, and are flat and spiny. Dragon-flies
hold their wings horizontally when at rest, and
the nymphs have rectal respiration; while the
damsel-flies hold their wings vertically when at
rest, and the nymphs have three caudal tra-
cheal gills (Fig. 56).

Caddice-flies (Trichoptera). — The larvae of
these insects are known as caddice-worms, and
live in water within protecting cases of fine
gravel, leaves, sticks, stalks or small shells,
•fastened together by threads of silk. They
crawl about carrying their cases with them.
When full-grown they change to pupcB within
the cases and at length emerge as four-winged
flies. During summer immense numbers are
attracted to lights at night. The wings are
hairy, and, at rest, are held like a roof over the back,
usually laid on water plants.

Fig. 55. — Nymph of
s t o n e-fi y {Pteronarcys
regalis).

The eggs are

Fig. 56.

-Dragon-fly {Libellula pulchella). Last nymphal skin and wings. Slightly
reduced. {After Folsom.)

Dobson-flies, Lace-wings, Ant-lions (Neuroptera). — Dobson-flies
are large insects with prominent biting mouth-parts and wings. Their
larvae live under stones in swift streams, and have rather conspicuous
tracheal gills. They become full-grown in about three years.

lOO ECONOMIC ENTOMOLOGY

Lace-wings are delicate pale-green insects with finely veined wings.
The larvae have large jaws, and owing to their habit of feeding upon
aphids are called aphis-lions. The pupae are
enclosed in a white cocoon of silk (Fig. 57).

Ant-lions are predaceous larvae, which lie
in wait for their prey at the bottom of funnel-
shaped pits. The adults have narrow delicate
wings.
{Chrysol''a)7%\St^rl Scorpion-flies (Mecoptera) —Scorpion-flies
duced. {After Folsotn.) have their head prolonged into a beak. The
larvae live in the ground and are caterpillar-
like. Both larva and adult are carnivorous.

ORDER MALLOPHAGA (BITING LICE)

Chief Families and Genera:

A. Antennae filamentous, exposed, 3- or 5-jointed; maxillary palpi absent;
mandibles vertical; middle and hind segments of thorax fused.
B. Antennas 3-jointed; tarsi with a single claw; infesting mammals.
■ — Trichodectidce.

Genus: Trichodedes.
BB. Antennae 5-Jointed; tarsi with two claws; infesting birds. — Philopteridce.
Genera: Docophorus, Lipeurus, Nirmus, Goniodes, Goniocoles.
A A. Antennae clavate or capitate, concealed, 4- jointed; maxillary palpi 4-
jointed; mandibles horizontal; middle and hind segments of thorax sepa-
rated by a suture.
. B. Tarsi with a single claw; infesting mammals. — Gyropida.
Genus: Gyro pus.
BB. Tarsi with two claws; infesting birds. — Liotheidce.
Genera: Menopon, Trinoton.
(Consult Bull. 5, n.s. Divison of Etomology, U. S. Dept. of Agriculture, by Osborn)

Although most commonly found on poultry, Biting Lice some-
times infest the larger domestic animals. They do not suck blood
but feed on the rough parts of the skin and at the base of hairs and
feathers, causing considerable irritation. Young chicks frequently
suffer severely from their attacks.

The most abundant species found on fowls is the common hen
louse (Menopon pallidum), a pale yellow active insect, 3^5 inch long,
with six legs (Fig. 58).

The eggs or "nits" are oval objects attached to the vanes and

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS lOI

barbs of the feathers, usually on the down feathers. They hatch in
8 to lo days and become full grown in 2 to 3 weeks.

Dampness, filth and warm weather favor their increase.

Control. — (a) Sanitary surroundings with access to a dust bath.
(b) Dusting with lice powder, such as insect powder, or one pre-
pared as follows: 3 parts gasoline, i part crude carbolic acid (90-
95 per cent.), or i part cresol. Mix together and add, with stirring,
plaster-of-Paris to take up all the moisture (about 4 qts. to i qt. of
Hquid). (c) Dusting with sodium fluoride.
All remedies should be applied more than
once.

Following are the common Mallophaga in-
festing domesticated birds:

A. Feather-lice Infesting Chickens:

1. Head nearly square, abdomen not con-
spicuously marked, ^^^5 inch long. —
Goniocotes hologaster Nitzsch (Lesser
Chicken Louse).

2. Head almost circular in front, nar-
rowed behind, thorax small; head,
thorax, and legs yellowish; white
stripes on segment of abdomen, 3^^
inch long. — Goniocotes abdominalis ^'^■
Piaget (Larger Chicken Louse).

3. Yellowish with black markings, uncommon. — Goniocotes hur-
netti Pack.

4. Smooth and shining, head squarish, }{q inch long, tawny, pubes-
cent. — Goniodes dissimilis Nitzsch.

5- Body elongated, smooth and shining, black margins. — Lipeurus

variabilis Nitzsch.
6. Yellowish, slender louse, }io inch long, common. — Menopon

pallidum Nitzsch (Hen or Chicken Louse).

B. Feather-lice of Ducks and Geese:

1. Head and thorax red with dark bands; abdomen whitish at
middle, brown at sides, 3^^ inch long. — Docophorus icterodes
Nitzsch.

2. White, smooth, and shining, on goose. — Lipeurus tadornce
Denny.

58. — Chicken louse.
{Menopon.)

I0 2 ECONOMIC ENTOMOLOGY

3. Large, 3^^ inch long, elongated, yellowish, head cone-pointed, on
ducks, — Lipeurus squalidus Nitzsch.

4. Large well-marked louse, 3^^ inch long, on ducks. — Trinotum
luridum Nitzsch.

5. White, almost transparent louse, on goose. — Trinotum lituratum
Nitzsch.

C. Feather-lice of Turkey:

1. Head with hind angles extending backward into bristly styles;
^^ inch long. — Goniodes stylifer Nitzsch.

2. Yellowish, elongated, flat pointed body, 3^7^ inch long. — Lipeurus
poly trapezius Nitzsch.

Orthopteroid Insects

The old Order Orthoptera is now broken into several new Orders by
the elevation of certain Families to ordinal rank. The relationship
of these and other allied orders is shown by the following grouping:
I. Sub-class: Orthopteroida.

Orders: Orthoptera, Phasmoidea and the allied orders Dermap-
tera and Thysanoptera.
IL Sub-class: Blattaeformia.

Orders: Mantoidea, Blattoidea and the allied orders Isoptera,
Corrodentia and Mallophaga.

Chief Economic Orthopteroid Orders:

A. Hind femora large and fitted for jumping. — Orthoptera (Locusts, Crickets, etc.
AA. Hind femora not large, not fitted for jumping.

B. Body elongate; abdomen without movable forceps.

C. Front legs spined and fitted for grasping.^ — Mantoidea {Mantids).
CC. Front legs not formed for grasping, legs long and slender. — Phas-
moidea (Walking slicks).
BB. Body elongate; abdomen with movable forceps; fore wings short and
horny, hind wings nearly circular. — Dermaptera (Earwigs).
BBB. Body oval, flattened; legs fitted for running.- — Blattoidea (Cockroaches).

ORDER ISOPTERA (WHITE ANTS)

FamUy TERMITID.S

This order is characterized by incomplete metamorphosis, biting
mouth-parts and net-veined wings that fold flat upon the back.

CLASSinCATION AND DESCRIPTION OF COMMON INSECTS I03

There is but one Family — the TermitidcB. The members of each
species live in communities in the ground or sometimes on trees and
include males, females and neuter workers and soldiers. They feed
upon vegetable fibre, and are often injurious to furniture, books and
wooden structures.

Termites are most abundant in tropical or semi-tropical countries.
A few species such as Leucotermes flavipes are found as far north as
Canada.

ORDER CORRODENTIA (BOOK-LICE)

Family PSOCID^

These insects have biting mouth-parts and are either wingless
or with roof-like wings. The Family PsocidcB includes the minute
book-lice which are often injurious to old books, herbaria and insect
collections. The most common species is Atropos divinatoria, a minute,
pale-colored wingless insect. It feeds upon the paste of book bindings
and upon decaying vegetable and animal matter.

Control. — When severe infestations occur, fumigate with sulphur
(2 lb. to 1000 cu. ft.) or with hydrocyanic acid gas.

ORDER BLATTOIDEA (COCKROACHES)

Family BLATTID.S

Genera and Species:

A. Last ventral segment of female abdomen plane not compressed; fore
femora rarely provided with spines.
B. Sub-genital stylets present in the males, upper wings of females short.
— Ischnoptera.

I. pennsylvanica brown, sides of pronotum yellow.
BB. Sub-genital stylets absent in the males. Upper wings of both sexes
long. — Blattella = Edohia = Phyllodromia.
B. germanica (Croton bug), length )^ inch.
A A. Last ventral segment of female abdomen compressed and divided; fore
femora spined.
B. Wing-covers not reaching tip of abdomen. — Blatta.
B. orientalis (Oriental Cockroach).
BB. Wing-covers reaching beyond the abdomen. — Periplaneta.

C. Wing-covers much exceeding abdomen. — P. americana.
CC. Wing-covers but little exceeding abdomen; a bright yellow
stripe on basal half of their outer margin. — P. australasice.

I04

ECONOMIC ENTOMOLOGY

Several injurious species of cockroaches occur: (i) American
Cockroach, (2) Austrahan cockroach, (3) Oriental cockroach, and (4)
German cockroach or Croton Bug.

I. American Cockroach {Periplaneta americanaL.), a native species,
is a large dark brown insect i)-2 inches long, with well-developed wings
in both sexes, 13^^-2 inches long; thorax with an obscure yellow border.
Eggs held within a capsule until hatched. Duration of life-cycle
about a year. Nocturnal.

Fig. 59. — The oriental roach {Blalla orienlalis): a, female; b, male. All
natural size. {After Marlalt, U. S. Bur. Ent.)

2. Australian Cockroach (Feriplanela australasia L.), ij^ inches
long; resembles preceding but the yellow band on thorax is much
brighter and more definitely limited. Upper wings have a dash of
yellow on each side. Abundant in the south.

3. Oriental Cockroach {Blatta orientalis Fol.) or "black beetle,"
is a nearly wingless dark brown or black robust form, about an inch
long— the male with wing cases one-half to three-fourths length of
abdomen; female wingless. Notably gregarious and larger than the
Croton Bug (Fig. 59).

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS I05

4. Gennan Cockroach or Croton Bug (Edobia germanica L.), has
a light brown thorax marked with two dark brown stripes. Both
sexes with well-developed wings. Active and wary, relatively small,
^8 inch long.

All the roaches have a foetid roachy odor, and are said to feed on
the bedbug (Fig. 60). They are particularly abundant in pantries,
kitchens and bakeries and they feed on almost any kind of dead animal
matter and cereal products. The eggs are produced in a brown cap-
sule which is often carried about for a time before deposited in a crev-
ice or nook.

Control. — A bait of powdered borax mixed with sweetened chocolate;
a trap of flour and plaster-paris and water; fumigation with hydro-

pic. 60. — The German roach {Ectohia germanica) : a, first stage; b, second stage;
c, third stage; d, fourth stage; e, adult; /, adult female with egg case; g, egg-case,
enlarged; h, adult with wings spread. All natural size except g. {From Riley.)

cyanic acid gas. Dust the runways or hiding places with sodium
fluoride mixed with flour by means of a dust gun or blower. Boric
acid is also effective.

ORDER MANTOIDEA (PRAYING MANTIDS)

Family MANTID.S

The Praying Mantids are predaceous insects and for centuries
have been looked upon as uncanny creatures both in the old and new
worlds. The most common American species is Stagmomantis Carolina,
but this form does not breed normally north of southern New Jersey,
Pennsylvania and Ohio. In 1899, however, the European species

Io6 ECONOMIC ENTOMOLOGY

(Mantis religiosa Linn.) was found in New York State, and in 1914
in Ontario.

The adult forms are elongated, with large grasping forelegs, long
prothorax and a small transverse head. The eggs are laid in shingled
masses on twigs, coated with a hard gummy substance.

ORDER PHASMOroEA (WALKING-STICKS)
Family PHASMID^E

This Family is represented by the common Walking-stick insect
{Diapheromera Jemorata, Say), a peculiar creature with long slender body
and legs. The outer wings are either wanting or very short.

Life-history. — The eggs are dropped singly in autumn from the shrubs
and rest on the ground all winter among the leaves, hatching in early
summer. The nymphs feed upon leaves, and reach maturity in late
summer and early fall, when they resemble the twigs upon which they
rest. Occasionally this insect becomes injurious on hazel and beech.

ORDER DERMAPTERA = EUPLEXOPTERA (EARWIGS)

European Earwig (Forficula auriculari a Linn.). — This insect is held
in check in Europe by parasites and other natural agencies but the
practical absence of these checks allows it to multiply rapidly in
America wherever it has been introduced. At Newport, R. L, it is a
serious pest of Lima-beans, dahlias, early roses, chrysanthemums,
clovers, grasses, etc.

The adult females hibernate in the soil, and the white eggs are laid
in the soil. The nymphs are night feeders. They are white at first
but gradually darken in color to a steel grey — 4 instars. Adults ap-
pear about the middle of July. They are rich reddish brown with
yellow brown wing-covers and legs; about ^^ inch long. The forceps
is nearly straight in the female, but curved in the male.

Control. — Use poison bait before July ist and spray plants with
arsenate of lead; collect by traps.

Labia minor Linn., also an adventive earwig from Europe, is widely
distributed in U. S. and Canada. Not of economic importance.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS I07

ORDER ORTHOPTERA (LOCUSTS, GRASSHOPPERS AND CRICKETS)

FAMILIES

A. Antennse shorter than body.— Acridid(e (Locusts or Short-horned Grass-
hoppers) .
AA. Antennae longer than body.

B. Tarsi 4-Jointed. — LocuslidcB {Long-horned Grasshoppers),
BB. Tarsi 3-jointed. — Gryllidm {Crickets).

AcRiDiD^ (Locusts or Short-Horned Grasshoppers)
Sub-families, Genera and Species (Figs. 61-63).

Sub-families:

A. Pronotum extending over abdomen; claws of tarsus without pulvillus;
size small. — Teltigince.

ppH-

cer

-fq.pl
oyp.

Pig. 61. — Abdomen of female Melanoplus bivittatus. A, lateral view; B,
dorsal view; C, central view; D, egg guide; au., the auditory organ; sp., spiracle;
ovp., ovipositor; g.pl., genital plate; p. pi., podical plate; cer., cercus. {After Lugger.)

AA. Pronotum not extending over abdomen; claws of tarsus with pulvillus;
size larger.

B. Prosternum with tubercle. — Acridince.
BB. Prosternum without tubercle.

C. Vertex and front of head meeting at an acute angle. — Tryxalincs.
CC. Vertex and front rounded. — (Edipodina.

io8

ECONOMIC ENTOMOLOGY

Genera of the TeUigina:

A. Antennae 12-jomted and pronotum rounded. — Batrachidea.
A A. Antennae 13-14-jointed; pronotum horizontal. — Tettix.
AAA. Antennae 22-jointed; pronotum horizontal. — Tettigidea.
(For species see Blatchley's Orthoptera of Indiana.)
Genera of the A cridince:

A. Wings as long or longer than the abdomen.

B. Pronotum sloping from median carina; extremity of abdomen in males
not swollen. — Acrid ium or Schislocerca.
BB. Pronotum flattened; extremity of abdomen in males swollen. —
Melanoplus.

Fig. 62. — -Abdomen of male Melanoplus hiviilalus. A, lateral view; B, dorsal view;
C, ventral view. {After Lugger.)

Species of Acridium:

A. Size large; antennae rather short. — A. americana.
AA. Size medium; antennae longer.

B. Color yellowish-brown or olive-green. — A. alutacea.
BB. Color rusty-brown; no yellowish stripe on dorsum. — A. rubiginosa.
Species of Melanoplus:

A. Apex of last ventral segment of male distinctly notched (Fig. 63) .
B. Length of body to tip of wing-covers 29-35 mm. — M. spretus.
BB. Length of body to tip of wing-covers 23-26 mm. — M. atlanis.
A A. Apex of last ventral segment of male entire, or at least obscurely notched.
B. Anal cerci enlarged at apex. — M. bivitlatus.
BB. Anal cerci tapering.

C. Species of medium size; anal cerci much narrowed, but without a
notch. — M. femur-ruhrum.
CC. Species of large size; anal cerci suddenly narrowed, making a
prominent right-angled notch on lower side. — M. difereniialis.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS IO9

Genera of the Tryxalince:

A. Foveolae of vertex present, and visible from above. Lateral carinas of
pronotum incurved. — Stenobothrus curlipennis.
AA. Foveolse absent; lateral carinas nearly parallel. — Chrysochraon conspersum.
Genera and Species of QLdipodina:
A. Wings with the disk yellow.

B. Apical half of wing dusky.

C. Dorsal aspect of head with a slight median carina which is quite
prominent in the central foveola. — Enco ptolophus sordidus.
CC. Dorsal aspect of head without median carina; central foveola
less distinct. — Chortophaga viridifasciata.
BB. With a dark band across the wings. — Spharagcmon (equate.
A A. Wings with the disk black. — Dissosleira Carolina.
AAA. Wings transparent with dark veins; tegmina smoky brown with darker
spots and yellowish blotches on sides. — Camnula pellucida.

Fig. 63.

-Tip of male abdomen of Melanoplus, dorsal view. A, M . femur-rubrum;
B, M. spretus; C, M. atlanis; D, M. differenlialis.

In the West the Rocky Mountain Locust {Melanoplus spretus)
did, and occasionally does, produce much injury to grain and other
crops. Another species more widely distributed is M. atlanis which
sometimes becomes migratory. The Red-legged Locust or Grasshop-
per {M . femur-rubrum) , the Two-striped Locust {M. bivittatus) and the
Pellucid Locust {Camnula pellucida) in the East and the Differential
Locust {M. diferentialis) in the South are the species that do most
injury.

Red-legged Locust or Grasshopper {Melanoplus femur-rubrum,
DeG.).^ — ^This locust is usually the most abundant form in the East,
and is most numerous in low grounds and cultivated fields where vege-
tation is more or less rank (Fig. 64).

Adult. — Of medium size, about an inch long; reddish brown in color;
tegmina sometimes without spots but usually spotted, surpassing
the hind femora, which are reddish brown; hind tibiae red with black

no

ECONOMIC ENTOMOLOGY

spines; cerci of male narrowing from tip to base and subgenital plate
narrower at apex than at base.

Fig. 64. — Red-legged grasshopper {Melanoplus fernur-r ubrum) : Above, adult
male; below, adult female. About twice natural size. (After W. R. Walton, U. S.
Bur. Ent.)

x^

-^

,

^Wt

VppP^^iipl

1

m.

^^^

'^H

Hi

1

1

P

-■ ^'-^'/'/MIw!

m

Fig. 65. — Locust ovipositing; egg pod in ground at right. Enlarged one-half.
{After Gibson, Ent. Circ. 5, Dept. Agric, Ottawa.)

Eggs. — Deposited in pod-like masses in the ground; oblong-oval.
Nymphs. — Vary in size according to age and month; all stages of
developing wings; grey to yellow; five moults.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS III

Life-history. — Nymphs hatch from eggs in spring; these mature in
August and September, when eggs are laid in the ground and over-
winter there (Figs. 65 and 66).

The Lesser Migratory Locust (Mela-
noplus atlanis Riley). — ^A native Ameri-
can species; often abundant in Eastern
Canada, causing serious injury. Com-
pared with M. femur-rubrum the fe-
male has a yellow under surface, and
more distinctly banded hind femora,
and the male has the apex of the sub-
genital plate notched, the cerci shorter
and less tapering, and longer tegmina
which are also more distinctly spotted.
It has a distinct patch of black on the neck or collar. Egg deposition
occurs from July to September. Mature forms appear from July ist,
and are often abundant in open sandy regions with sparse vegetation.

Fig. 66. — Egg pod of locust
opened to show arrangement of
eggs; individual eggs at side,
natural size. {After Gibson, Ent.
Circ. 5, Dept. Agric, Ottawa.)

^^

x!=*^N

Pig. 67. — Lesser migratory grasshopper {Melanoplus atlanis): Above, adult
male; below, adult female. About twice natural size. {After W. R. Walton, U. S.
Bur. Ent.)

The nymphs undergo five moults; the eggs are deposited in the ground
in small pod-like capsules, and hatch in the spring (Fig. 67).

112

ECONOMIC ENTOMOLOGY

Differential Locust (Melanophis diferentialis Uhler). — This locust
is larger than those described above, about i3''^ inches long, and is dark
brownish-green or olive-brown in color. The hind legs are yellow with
black basal tibial ring and black spines. The subgenital plate short
and broad, and the cerci of male boot-shaped. It is fond of the Greater
Rag-weed. It is a southern form.

Fig. 68. — Two-striped grasshopper {Melanoplus bivitlatus): Above, adult male;
below, adult female. Twice natural size. {After W. R. Walton, U. S. Bur. Ent.)

Two-striped Locust {Melanoplus hivittatus Say). — This locust is
not so large as the Differential locust, being about i^^i inches long,
and is dull olive-brown above and yellowish beneath. A narrow yel-
lowish stripe runs along each side from the eye to the tip of the teg-
men. The hind femora are yellow, and the hind tibiae coral red with

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS II3

black spines. The cerci of the male are stout, and two lobed; the
subgenital plate is narrow. The young and newly transformed adults
are greenish (Fig. 68). Its transformations are later than those of
M. atlanis.

Clear-winged Locust (Camnula pellucida Scudder). — This locust
occasionally does serious injury' in the West, and frequents high dry
soil. It is of a light brown color; the tegmina are smoky brown with
darker spots and yellowish blotches on the sides and a yellowish brown
stripe along each humeral angle. The wings are transparent and pellucid
with dark veins. Body of male 19 mm. long, of female 22 mm. It
is often associated with M. atlanis in the East, and is the earliest of the
grasshoppers (Fig. 6g).

^e-^

Fig. 69. — Pellucid or clear-winged grasshopper {Camnula pellucida): Adult female.
About twice natural size. {After W. R. Walton, U. S. Bur. Ent.)

Carolina Locust {Dissosteira Carolina Linn.). — This locust is larger
than the preceding species and is of a pepper-and-salt color, with varia-
tions from grey to yellow or reddish. The hind wings are black
margined with yellow. It is sometimes injurious to corn, wheat, alfalfa
and soy beans.

Natural Enemies of Locusts. — Robber-flies, bee-flies, flesh-fly and
blow-fly larvae, digger wasps and bhster-beetle larvae; birds and domes-
tic fowls; toads, snakes, moles, mice, ground squirrels, skunks and hogs;
mites, spiders, "hair-snakes," etc.

Control of Locusts. — (a) AppHcation of poisoned baits (see Part IV,
p. 398). {b) Use of hopperdozers. {c) Destruction of eggs by fall
cultivation, {d) Co-operation of communities.

(Consult U. S. Com. Rept. or. Rocky Mt. Locust, 3 vols.. Farmers' Bulls. 691 and 747, U. S. Dept.
Agr.; Giro, s, Ent. Br. Dept. Agr., Can.; Cornell Bull. 378; Mich. sp. Bui. 83)

114 ECONOMIC ENTOMOLOGY

LocusTiD^ (Long-horned Grasshoppers or Locusts)
More Common Genera and Species

A. Wingless or with rudimentary wings and wing-covers.

B. Pronotum not extended over meso- and metanotum. — Ceuthophilus.
BB. Pronotum extended over meso- and metanotum. — Thyreonolus.
AA. Winged.

B. Tegmina expanded in the middle.

C. Tegmina much broadened in the middle, concave. — Cyrtopkyllus.
CC. Tegmina somewhat broadened in the middle, not concave.
D. Ovipositor very small. — Microcentrum.
DD. Ovipositor of medium size. — Aniblycorypha.
BB. Tegmina not expanded in the middle.

C. Vertex of the head with a conical projection forward. —
Cotiocephalus.
CC. Vertex of the head without a conical projection.

D. Ovipositor straight or very nearly so; insect small. —
Xiphidium.
DD. Ovipositor curved; insect large.

E. Ovipositor curved sharply upward. — Scudderia.
EE. Ovipositor sword-shaped. — Orchelimum.
Species of Ceulhophilus:

A. Fore femora about as long as pronotum. — C. maculalus.
AA. Fore femora longer than pronotum. — C. brevipes.
Species of Thyreonolus:

A. Pronotum well rounded behind. — T. dorsalis.
AA. Pronotum nearly square. — T. pachymerus.

The members of this family are seldom of sufl&cient importance
economically to require special treatment. The katydids, shield-
backed grasshoppers, cricket-like grasshoppers, and meadow grass-
hoppers belong here and are interesting objects of study. Recently
it was found that two species of katydids {Scudderia furcata Brunner
and Microcentrum rhombifolium Sauss.) are injurious to oranges in
California, often causing serious loss. (Bull. 256, Bur. Ent. U. S.
Dept. Agr., 1915.)

Gryllid^ (Crickets)
Genera and Species

A. Fore tibiae broad, fitted for digging (Fossorial Crickets).

B. Insect small; antennae ten- to twelve-jointed. — Tridactylns.
BB. Insect large; antennae many-jointed. — Gryllotalpa.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS II 5

AA. Fore tibiae slender.

B. Hind femora stout (True Crickets).

C. Last segment of the maxillary palpi of the same length as the
next to the last. — Grylliis.
CC. Last segment of the maxillary palpi double the length of the next
to the last. — Nemobius.
BB. Hind femora slender (Tree Crickets).- — CEcanthus.
Specks of Cryllus:

A. Black field crickets.

B. Ovipositor 13-14 mm. long; male more slender. — G. pennsylvanicus .
BB. Ovipositor 18 mm. long; male stout. — G. ahhrevialus.
AA. Straw colored house crickets.— <?. domeslicus.
Species of Nemobius:

A. Ovipositor longer than hind femora and straight; color blackish, arranged
in longitudinal bars. — N. fasciatus.
AA. Ovipositor shorter than hind femora and arcuate. — N. exiguus.

Fig. 70. — Markings on basal segments of antennae of CEcanthus: a, CEc. niveus;
b, CEc. angustipennis ; c, CEc. nigricornis; d, do.

Species of CEcanthus (Fig. 70):

A. Antennae with one black mark on each basal joint.

B. Black marks like small rounded dots. — CE. niveus.
I BB. Mark on first joint long and hooked, that on second oblong. — CE.

angustipennis.
AA. Antennae with two black marks on the first basal joints.

B. Antennae wholly black, also head, thorax and legs. Marks on first
joint of antennae generally connected at apex. — CE. nigricornis.
BB. Pale greenish white; marks on antennae elongate, parallel, distinct. —
CE. 4-punctalus.
AAA. Antennae without marks on first joints, wing-covers broad; head and first
joints of antennae pink. — CE. latipennis.

The Pennsylvania Field Cricket {Gryllus pennsylvanicus Burm.). —
The field cricket is omnivorous and seldom does enough damage to
merit special attention. It is fond of grain, however, and often enters
barns destroying a considerable amount of grain.

Adult. — A large black cricket existing in two forms — the commoner
short-winged form in which the wings are rudimentary and the long-

ii6

ECONOMIC ENTOMOLOGY

winged form in which they project beyond the tip of the tegmina. * The
tegmina are deep black to grayish brown, in the male reaching the tip
of the abdomen, in the short-winged female not quite so long and in
the long-winged form slightly surpassing the tip of the abdomen. The
ovipositor never exceeds the body in length. Length of insect 16-20
mm. (Fig. 71).

Eggs. — ^ Yellow, cylindrical, laid in the soil in late summer and
autumn in Quebec, in June and July farther south.

Nymphs. — In the north the nymphs hatch
in early summer from hibernated eggs; in the
neighborhood of Indiana they hatch in July
and August and hibernate.

Snowy Tree Cricket {(Ecanthus niveus
DeG.). — Sometimes injures apple and plum
trees by egg-punctures, and occasionally eats
holes in the ripe fruit (Fig. 74).

Adult. — Ivory-white tinged with green, 3^^
inch long; wing-covers nearly twice as long as
abdomen; those of male flattened, crossed by
oblique veins, semi-transparent and broader
than body, those of female wrapped close
about the body; ovipositor short, straight and
tipped with black; maxillary palpi relatively
long. July-October.

Eggs. — Elongate, cylindrical, yellow, 3^^
^'''^^'^^A~^'TfT^T' inch long; laid singly in punctures in the bark

vania field cricket (Gyllus ° ' ® -' ^

pennsyivanicus) . (After of Smaller branches of apple, plum and peach,
^''sger.) jj^ ^j^g f^l^. hat(,i^ jn May and June.

Nymphs. — Feed on plant-lice and other insects.

Black-horned Tree Cricket {(Ecanthus nigricornis Walker). — Con-
sult Bull. 388, N. Y. Ag. Exp. St.) Injures blackberry and raspberry
canes by egg punctures, and carries spores of cane-blight and other
diseases (Figs. 72 and 73).

Adult. — Greenish white; head and pronotum black or barred with
black; body black beneath and yellowish-green above; antennae long,
mostly black; wing-covers as in (E. niveus; head, thorax and legs mostly
black. Probably feeds on flies.

Eggs. — Similar to those of (E. niveus; laid in a row of punctures

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS I17

Fig. 72. — Black-horned tree cricket {CEcanlhus nigricornis). Female above, mal
below. {After Lugger.)

Fig. 73. — Egg punctures and eggs in raspberry by the black-horned cricket

(CE, nigricornis).

Il8 ECONOMIC ENTOMOLOGY

often 2 inches long, each row containing about 30 eggs; hatch in
May and June.

Nymphs. — Feed on plant-Hce and other insects; full grown late
July and August.

Control. — Prune out infested twigs and burn them.

Other species of (Ecanthus deposit eggs in galls on willows, and in
the stems of Helianthus, Solidago, etc.

Fig. 74. — CEcanthus niveus ovipositing. {After Parrott.)
ORDER THYSANOPTERA (THRIPS)

(Consult Tech. Ser. No. 12. Pt. Ill, and No. 21. Bur. Ent., U. S. Dep. of Ag.)

A. Female with a saw-like ovipositor, last segment of abdomen of female
conical, that of male broadly rounded; wings usually present, the fore pair
the stronger.
B. Ovipositor curved upward; antennas 9-jointed; fore wings broad and
rounded. MololhripidcB. — ^Genus JEolothrlps.
BB. Ovipositor curved downward; antennae 7- to lo-jointodj wings usually
narrow and pointed. — ThrlpidcB. Genera: Thrips, Euthrips, Helio-
thrips, Anaphothrips.
AA. Female without a modified ovipositor, last segment of abdomen tubular
in both sexes; wings often absent, but when present similar in structure.^
Phloeothriplda. Genera: Phlxothrips, Trichothrips, Cryplothrips.

classification and description of common insects ii 9

Thripid^ (Thrips)

Grass Thrips (Anaphothrips striatus Osborn).— Feeds by sucking
the juices of various grasses such as timothy, Kentucky blue, couch
grass and oats.

Adult. — Small, 3^f g inch long, yellowish or brownish-yellow; four
narrow wings fringed with hairs; feet bladder-like; parthenogenetic;
May-June. Hibernate.

Eggs. — First brood laid in spring, hatching in 10 to 15 days; summer
eggs hatching in 4 to 7 days.

Nymphs. — Become full grown in spring in about 2 weeks, summer
forms in 4 days. Life-cycle in 12 to 30 days.

" Thrips injury on the leaves shows as minute dots or lines usually
running parallel with the leaf veins and remaining white."

Pear Thrips {T(Bniothrips inconsequens Uzel). — (Consult Bull.
80, Part 4, U. S. Bur. Ent., 1909; Bull. 343, N. Y. Ag. Exp. St., 191 2; Bull.
15, Ent. Br. Dept. Ag. Can., 1918.) A pest in central California and
British Columbia, along Hudson River and in Pennsylvania to pear,
apple, cherry and plum. Chief injuries done by adults to the buds in
spring (Fig. 75).

Adult. — Minute, slender, dark brown, 3^^5 inch long; wings fringe-
like and fiat along the back. Enters fruit buds in early spring. One
brood a year.

Eggs. — ^Laid by a sharp, curved, saw-toothed ovipositor beneath
epidermis of fruit and leaf stems as the trees come into bloom, causing
"bleeding," and giving the bud a shrivelled, scorched appearance when
infestation is heavy.

Nymphs. — Hatch out in blooming time and become full grown in
about 2 weeks. They then drop to the ground and form a pupal cell
some distance below, where they hibernate. The pupal stage is an
inactive stage and lasts about 2 months before the adult appears.

Control. — Spray early with kerosene emulsion or soap solution, or
distillate oil emulsion, to which is added nicotine extract.

Greenhouse Thrips (Heliothrips hcBmorrhoidalis Bouche). — This in-
sect injures the leaves of many greenhouse plants which first become
spotted, then blotched and finally wilted. Drops of a reddish fluid,
turning black, cover the leaves. (Consult Bull. 64, Pt. 6, Bur. Ent.,
U. S. Dept. of Agriculture.)

I20

ECONOMIC ENTOMOLOGY

^y.y\..,^^.

Fig. 75. — ^Pear thrips {Tceniothrips inconsequens): i. Adult; 2, eggs; 3 and 4, larvae;
5 and 6, nymphs or pupae; 7, head (side view) . All greatly enlarged. {After Moulton,
U. S. Bur. Enl.)

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 121

Adult. — One-fifteenth inch long; head and thorax dark brown,
abdomen yellowish brown; antennas with 8 segments; 3 to 4 weeks for a
generation; fore- wings with two, hind- wings with one longitudinal vein.

E^gs. — Hatch in 5 to 8 days; laid singly in leaf tissue; colorless and
bean-shaped.

Nymphs. — Mature in 20 to 25 days.

Onion Thrips or "White Blast" (Thrips tabaci Lind.). — Attacks a
large variety of garden plants. Found on bulbs of onion in loose soil
and at axils of leaves. Punctures the tissues and sucks the sap, giving
the field a whitish appearance. Produces also scuUions or thick
necks.

Fig. 76. — Wheat thrips (Euthrips Iritici) . Greatly enlarged. (After Folsom.)

Adult. — One-twenty-fifth inch long, active, slender, yellowish tinged
with black, two pairs of bristly narrow wings which fold along the back.
Probably winters over in the rubbish on the ground; life-cycle about
3 weeks, hence several generations in a season.

Eggs. — ^Laid singly in spring or early summer within the leaf tissue,
3^foo i^ch long, elongate and curved; hatch in about 4 days.

Nymphs. — Transparent at first, later greenish-yellow; mature in
II or 12 days.

Control. — Spray with solution of nicotine sulphate and whale oil
soap (4 oz., 4 lb., 40 gal.)

122 ECONOMIC ENTOMOLOGY

Wheat or Strawberry Thrips {Euthrips tritici Fitch). — The most
common thrips and found on many cultivated plants. Injurious to
strawberry, apple, peach and wheat. Several generations in a season
(Fig. 76).

Adult. — Small, ^'20 inch long, brownish yellow.

Eggs. — Small, whitish, curved oblong; laid singly in lower part of
calyx and in flower stalk of strawberry; hatch in 3 days.

Nymphs. — Three moults; mature in 9 or 10 days.

This thrips produces "button" strawberries.

Control. — Spray with nicotine or kerosene emulsion.

ORDER HOMOPTERAi
Chief Economic Families

A. Tarsi i or 2-jointed; antennae usually prominent; beak apparently arising
from sternum. — Group Slernorhynchi.
B. Tarsi i-jointed; adult male with beak and 2-winged; female wingless
with body scale-like, or gall-like, or grub-like, and covered with waxy
secretion. — Coccidce (Scale Insects), p. 123.
BB. Tarsi 2-jointed; wings usually 4.

C. Wings white, opaque. — Alcyrodidce (White-flies), p. 151.
CC. Wings transparent.

D. Legs long and slender; antennae 3-7-jointed. — Aphldida
(Plant-lice), p. 136.
DD. Hind legs fitted for leaping; antennae 9 or lo-jointed. —
Psyllida (Jumping Plant-lice), p. 152.
A A. Tarsi 3-jointed, antennae minute; beak evidently arising from mentum. —
Group Auchenorhynchi.

B. Ocelli 3; males with musical organs. — Cicadidcc (Cicadas), p. 156.
BB. Ocelli 2 or wanting; males without musical organs.

C. Antennae inserted on side of cheek beneath the eyes. — Fulgorida.
CC. Antennae inserted in front of and between the eyes.

D. Prothorax prolonged into a horn above the abdomen. —
MembracidcB (Tree Hoppers), p. 157.
DD. Prothorax not prolonged above the abdomen.

E. Hind tibiae armed with two stout teeth and tip crowned
with short stout spines. — Cercopida (Spittle Insects),

P- 153.
EE. Hind tibias with a double row of spines below. —
CicadellidcB or the Jassoidea{L&?ii Hoppers), p. 154.

' The old order Hcmiplera is here broken up into three orders viz.: Homoptera,
Hemipiera and Siphunculata (see p. 94).

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 23

I. CocciD^ (Scale Insects)

Chief Sub-families and Genera

Chief Sub-fatnilies:

A. Abdominal spiracles present on each segment; males with compound eyes;
adult females with white waxy lamellae. — Orlhezince.
AA. Abdominal spiracles absent; males with simple eyes.

B. Concealed beneath a "scale," formed partly of larval exuviae, partly
of secretion; abdomen ending in a "pygidium. " — DiaspincE (Fig. 79).
BB. Naked or covered with a waxy secretion, but not beneath a "scale;"
abdominal pygidium absent.

[ C. Extremity of abdomen cleft; anal orifice closed above by a
pair of triangular plates, anal ring fringed with setae; waxy
scale not separable from the insect. — Coccina.
CC. Extremity of abdomen not cleft; no anal triangular plates, anal
ring without setae. — Dactylopina (Fig. 81).
Chief Genera of the Diaspina:

A. Scale of female circular to oval with central, sub-central, or sub-marginal
exuvia.
B. Scale of male resembling scale of female in color and texture; only
slightly elongated.
C. Pygidium with 6 groups of circumgenital gland-orifices. — Com-
slockiella.
CC. Pygidium with less than 6 groups of gland-orifices.

D. Chitinous processes much elongated. — Chrysomphalus.
DD. Chitinous processes smaller and shorter or wanting. —
Aspidiotus (Fig. 79).
BB. Scale of male white, delicate and carinated.

C. Dorsal spinnerets irregular; exuvia usually sub-central. — Diaspis.
CC. Dorsal spinnerets in distinct bands; exuvia terminal in 2d
stage female and marginal in a.d\x\t.—Aiilacas pis.
AA. Scale of female elongated with exuvia at one extremity.

B. Scale of male similar to scale of female, but smaller; five groups
of gland-orifices. — Lepidosaphes.
BB. Scale of both sexes white, that of male small, with parallel sides
and carinated. — Chionaspis.
BBB. Scale of female brown, that of male white and carinated.— fl^ewi-
chionaspis.
Chief Genera of the Coccina:

A. Naked or covered only by a filmy secretion.

B. Flat or slightly convex; dermis alveolate. — Coccus.
BB. Very convex, usually hemispherical; hard when mature.

C. Dermis with coarse polygonal pitted areas. — Saissetia.
CC. Dermis microscopically tesselate, or appearing smooth. —
Lecanium.

124 ECONOMIC ENTOMOLOGY

AA. With a strong cottony secretion; secreting an ovisac; body more or less
chitinous without dorsal patches of secretion. — Ptilvinaria.
Chief Genera of the Daclylopina:

A. Female globular or reniform, in a hard shell; larva fringed with spines. —
Kermes.
A A. Female not as above; anal ring with eight hairs.

B. Adult surrounded by secretion but dorsally naked. — Gossyparia.
BB. Adult forming a cottony sac; caudal lobe long. — Eriococcus.
AAA. Female with soft powdery oval unarmored body; anal ring with six hairs.

B. Antennae normally with 8 segments, sometimes 7; tarsus not toothed. —
Pseudococcus (Fig. 81).
BB. Antennae normally with 9 segments; tarsus toothed. — Phenacoccus.

Scale insects are typically bark-lice, being minute sucking insects
covered with a mealy or cottony waxy secretion. Some, like the Mealy
Bugs, secrete a cottony material; some, like the Lecaniums, secrete
a waxy hard continuous layer which forms a protection for the back;
while others, like the San Jose Scale and the Oyster Shell Scale, pos-
sess true scale-like coverings, composed partly of a waxy secretion
and partly of moulted skins, beneath which the insect lives.

For a short time after birth Scale insects crawl about, but soon they
settle on the bark or leaf and begin sucking the sap. After a few
moults the females lose their legs, eyes and feelers. The male adult
insect is, as a rule, an active 2-winged insect with legs, eyes, feelers,
but no mouth. In most species the females lay eggs (oviparous),
but in a few the young scale insects are born alive (viviparous), i.e.,
the eggs hatch within the body of the mother.

(Consult Comstock's republished papers, Bull. 372, Cornell; the 'Coccidae of
Ohio" by Sanders; "Some Scale Insects of Mississippi" by Herrick; "The
San Jose and other Scale Insects" by Lochhead; "Coccidae of Indiana" by
Dietz and Morrison; and Bull. 6, Tech. Series, Div. Ent., U. S. Dept. Agr.)

Hard Scales (Diaspin^)

Following are the most common economic orchard forms: ^

Oyster Shell Scale (Lepidosaphes ulmi Linn.). — (Consult Farmers'
Bulletin 723, U. S. Dep. Ag.) A cosmopoHtan insect of European
origin and one of the most common pests of the orchard and of shade
trees 'and shrubs. Single-brooded in the North but double-brooded in
the Middle and Southern States (Fig. 79).

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 25

Adults. — Female scale oyster-shell shaped, narrow, }8~}io inch long,
brownish-black; male scale smaller and ovate.

Eggs. — Yellowish-white, laid in September-October under the
female scale (50-60). Destroyed by a mite Hemisarcoptes malus.

Nymphs. — The eggs hatch in late May or early June, or shortly
after the apple blossoms fall, into active 6-legged pale yellowish larvae,
the females moulting twice and the males once. The exuviae are
yellowish.

Parasites. — Parasitized by Aphelinus, Mytilaspidis, Anaphes, and
Chiloneurus and preyed upon by lady-birds, mites and birds.

Fig. 77. — Female San Jose scale, mature female insect removed from beneath it.
Greatly enlarged. {After Alwood.)

Scurfy Scale {Chionaspis furfur a Fitch). — ^A native insect, occur-
ring on pear, apple, gooseberry, and black currant.

Adult. — ^Scales white; female scale ovate, 2-3 mm. long, male
scale smaller (i mm.) and 3-ridged with parallel sides (Fig. 80).

Eggs. — Purplish-colored; laid in the early fall and found under the
female scale in winter.

Nymphs. — These hatch about the middle of June and the female
larvae moult twice. The male has one moult. As in the case of the
Oyster Shell Scale there is but one brood a season in the North and two
in the South.

Parasites. — Parasitized by Ablerus clisiocampcB How., a chalcid
and preyed upon by Tyroglyphus malus and Chilocorus bivulnerus.

126 ECONOMIC ENTOMOLOGY

San Jose Scale {Aspidiotus perniciosus Comst.). — China is probably
the home of this scale. It became estabhshed at San Jose, Cal., about
1870, and was introduced into Eastern nurseries in the U. S. about
1886-7, and into Ontario about 1896. Occurs on orchard trees,
bush fruits, and many perennials and annuals. On badly infested
branches the scale presents the appearance of dark-grey scurfy patches,
and on fruit there is often a purplish discoloration about the scale.

Adult.— Th.e. female scale is circular, ^-'5 inch in diameter, with a
central exuvium surrounded by a yellowish ring. The male scale is

Fig. 78. — a, Winged San Jose scale (much enlarged) ; b, young scale insect (enlarged

125 times).

oval, twice as long as broad, with a long dark exuvium showing a
nipple toward the small end of the scale. The San Jose scale winters in
the half-grown state. Early in spring the winged males appear, and
the females resume growth. The male moults thrice and the female
twice. In early June the females begin to produce living young. The
period of production lasts about six weeks during which time each
female produces on an average 400 young. The females mature in
35 to 40 days, and the males in about 25 days after their birth. There
are three or four broods in northern orchards (Figs. 77 and 78).

Nymphs. — The half-grown scale is black, and shows a central nipple
surrounded by one or two depressed rings.

Parasites. — The following Lady-birds feed on the San Jose Scale:
Chilocorus bivulnerus, Pentilia misella and P. suturalis.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 27

The chief Chalcid parasites are Prospaltella perniciosa Tower,
Aphelinus fuscipennis How., and A. diaspidis How., but the percentage
of parasitism is too low for eflfective control.

Fig. 79. — Pygidia of Aspidiotus. Showing the characteristic differences in
five common species. Greatly enlarged. D, dorsal surface; V, ventral surface.
{After Sanders.)

Control. — Plant fumigated nursery stock; spray with hme-sulphur
wash (sp. gr. 1.03) before the buds burst; spray with certain miscible
oils (see Part IV).

The three closely related species, Putnam Scale (A. ancylus Tutn.)
wintering in nearly full-grown condition and oviparous, the eggs

128

ECONOMIC ENTOMOLOGY

halchinjf in June-July, the Forbes Scale (A. Jorbesi John.), and the
Curtis Scale (.1. ostrecejormis Curtis) (Fig. 79), are difficult to dis-
tinguish from the San Jose Scale, and are also found in orchards.
A comparison of the pygidium, or the fused posterior abdominal seg-
ments, under the microscope enables one to identify the adults of these
species. On the dOrsal surface of the pygidium are the anal opening
and the glands that secrete the wax of the scale. On the ventral sur-
face are the vaginal opening and 4 or 5 groups of spinnerets (wanting
in the San Jose Scale). The margin of the pygidium is modified into

A B C

Fig. 80.— Three common orchard scales. A, San Jose scale; B, oyster-shell scale

C, scurfy scale.

lobes with thickenings, dorsal and ventral spines, and plates character-
istic of each species (Fig. 79).

Euonymus Scale (Chionaspis eiionymi Comst.) is a common pest of
Euonymus in the Eastern United States. Two broods a season.
Female scale elongate-oval, brown, with yellow exuvia, convex; male
scale white, parallel-sided, 3-ridged, with yellow exuvia, much smaller
than female scale.

Rose Scale {Aulacaspis rasa. Bouche). — Attacks rose, raspberry,
blackberry, etc.

Female scale snow-white, nearly circular, thin and flat, 3^f 2 iiich
in diameter; with two light yellow exuviae at margin; oviparous. Male
scale shorter, narrower, 3-ridged. Hibernates in all stages, hence
all stages may be found on one infested plant. Two or three broods a

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 29

year. Infested canes may become covered as if white-washed. Para-
site: Aphelimis diaspidis How., a chalcid.

Control.— {1) Trim out all badly infested canes before spring; (2)
spray with whale-oil soap (i lb, to i gal. water) or lime-sulphur in
early spring.

Soft Scales (Cogging)

Plum Scale, or EuropeanFruitLecanium {Lecanium corni Bouche). —
This scale, also called the New York Plum Scale, is sometimes abundant
in plum orchards. It occurs also on peach, apricot, pear, quince,
currant, blackberry, ash, elm, etc.

Adult. — Female scales conspicuous brown objects, "like small
halved peas," adhering to branches and twigs. Full grown in June.
Male scales much smaller, flatter, more elongate, and of a whitish
color; male insect dehcate, with two whitish wings; emerges in May
from scale.

Eggs. — Deposited under the scale in early June; white; hatch in
about a month.

Nymphs. — Emerge from beneath the mother scale and crawl to
the leaves in July; secrete much honey-dew. About the end of August
or in September they begin to migrate from the leaves to the twigs
and branches where they hibernate. In early spring (April) they begin
feeding again and grow rapidly, maturing in June.

Parasite. — Coniys fiisca.

Control. — Spray with a miscible oil (i to 15) before buds burst;
spray about July ist with Black leaf 40 and soap.

Terrapin Scale {Lecanium nigrofasciatum Perg.).- — (Consult Bull.
351, Bur. Ent. U. S. Dept. Agr., and Circ. 88.) Attacks shade trees,
such as maple, basswood and birch, and orchard trees, such as apple,
plum and peach. A native insect.

Adidt. — Female nearly hemispherical, reddish, 1-7 inches long,
mottled with radiating streaks of black conspicuous about the margin.
The presence of a double mid-dorsal row of 25-40 low subconical append-
ages appearing Hke pores, extending from near the anal lobes to nearly
above the sucking mouth-parts is quite characteristic. Adult of male
a minute, delicate 2-winged insect with rose-red body marked with
dark and with heavy brown thoracic band, appearing early in August;

130 ECONOMIC ENTOMOLOGY

male scale smaller than female, elongate, slightly convex, and greenish
white. Viviparous, young born June- July. One brood a year.

Nymphs. — Female scales nearly full grown by autumn, and winter
as such. Mature early in spring.

Control. — A 20-25 per cent, kerosene emulsion or miscible oil ap-
plied in dormant seasons destroys the hibernating females, or flour-
lime sulphur just before the young migrate to the leaves. Coccophagus
sp., a chalcid, is an important parasite.

Cottony Maple Scale (Fulvinaria vitis L.). — Occasionally becomes a
serious pest of shade trees, such as the soft maple, box-elder, bass-
wood, etc.

Adult. — Conspicuous on account of the cotton-like waxy masses
projecting from beneath the brown scale of the female. Female scale
"elliptical, convex on the back with a low rounded median ridge; pale
green or whitish yellow, marked with black or brown." Male insect
winged, with two long caudal filaments, and long antennae.

Eggs. — Minute, oval, pale yellowish; enclosed in the secretion of
waxy threads; about 3000 eggs laid by each female, in June and July.

Nymphs. — At first active and crawling, with six legs; later they
settle and secrete a thin waxy covering on their backs. Females
fertilized by the males in late summer. In autumn they migrate from
leaves to twigs where they remain all winter.

Parasites. — Coccophagus lecanii Sm., C. flavoscutellum Ashm. —
chalcids.

Control. — Spray in early spring with Black Leaf 40 and whale-oil
soap.

Golden Oak Scale {Asterolecanium variolosufn Ratz). — A small,
yellow, round, convex scale often coating twigs of oak. The nymphs
appear in May- June.

Cottony Grass Scale (Eriopeltis festuccgFonsc). — Often abundant
on stems of grasses in the maritime provinces; forming conspicuous
compact oval tufts of cotton wool, the egg-sacs. The eggs hatch in
spring and the scales become full grown in July. Toward the end of
July the eggs are laid in the cottony sacs.

Elm Bark -louse (Gossyparia spuria Modeer). — The females are dark
red, bordered with white wax; }{q inch long; arranged irregularly along
cracks or fissures in the bark of trunks or Hmbs. The young appear
in late June or early July and settle along the mid-veins of the leaves

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 131

and on the green tips of twigs. In Sept.-Oct. they migrate back to
the twigs. Winter is passed as partly grown insects.

Mealy Bugs (Dactylopin^)

Greenhouse plants are often injured by Mealy Bugs, which are
mealy in appearance and are able to move about freely. The scale is

Orthepa
insignis

Ps.longispinu5 ^ Kermes pubescens

Fig. 81. — A, Pseudoccus citri showing adult female, anal ring and penultimate
segment (i), antenna of adult female (2). B, Pseudococcus longispinus, showing
adult female, antenna (i), anal ring and penultimate segment (2). C, Kermes
pubescens. D, Orlhezia insignis. E, Pseudococcus trifolii, showing anal ring and
penultimate segment (3), anterior leg of adult female (4), and antenna of adult
female (5). (After Sanders.)

absent and at maturity they secrete a cottony sack within which are
deposited the cream-colored eggs. The following species are common:

132

ECONOMIC ENTOMOLOGY

Fig. 82. — Hemispherical scale (Saissetia hemisphaerica) on fern. Natural size.

(After Forbes.)

Fig. 83. — Hemispherical scale, enlarged. (After Forbes.)

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS I33

Long-tailed Mealy Bug {Pseudococcus longispinus Targ.). — A small
mealy coated insect, viviparous, occurring on Coleus, ferns, croton,
Poinsettia and citrous plants (Fig. 81).

Citrus or Greenhouse Mealy Bug {Pseudococcus citri Risso). — Ovi-
parous; occurs on Coleus, ferns and citrous plants. Common (Fig.
81).

Clover Root Mealy Bug {Pseudococcus trijolii Forbes). — Occurs near
the crown of second year red and white clovers in clusters, often accom-
panied by ants. Two forms exist — winter females, hatched from eggs
in the fall, producing larva; in the spring, some feeding on the roots and

Fig. 84. — Aspidistra scale
(Hemichionaspis aspidistrae). Fe-
male scale, enlarged. {After
Forbes.)

Fig. 85. — Male scale of the
Aspidistra scale, enlarged.
{After Forbes.)

others on the leaves; and summer females, producing several generations.
Oviparous females lay eggs in the fall after mating with males (Fig. 81).
Woolly Maple Leaf Scale {Phenacoccus acericola Walsh and Riley).
— A pest of maple trees, often confused with the Cottony Maple Scale.
Oviparous, 3^^ to 3-^ inch long, yellow, rounded-oval.

Other Greenhouse Scales

Lemons, crotons, oleanders, ivies, etc. in greenhouses are frequently
attacked by species of Coccus, Saissetia, AspidlotusjChrysomphaUts,

134

ECONOMIC ENTOMOLOGY

Orthezia and Hemichionaspis in addition to the Mealy Bugs already
described.

Soft Brown Scale {Coccus hesperidum Linn.). — An oval, flat scale,
straw colored to dark brown; viviparous. Occurs on oleander, Cycas,
ivy, rubber plant, box elder.

Hemispherical Scale {Saissetia hemisphcerica Targ.). — An oval,
polished, rich brown scale; oviparous. Occurs on palms, orchids, ferns,
asparagus, oleanders (Figs. 82 andj83).

g^Q^^^^^ginnniEEffi

MW<i^

Fig. 86. — Types of antennae of aphids: a, Chailophorus; b. Aphis; c, Schizoneura;
d, Pemphigus (apterous); e, Chermes; f, g, sensoria.

Oleander or Ivy Scale {Aspidiotus hederce Vail.). — A circular, flat,
grey or white scale, with a pale orange-colored centre. Occurs on
oleander, ivy, box wood, orange, palm, cycad.

Circular Scale (Chrysomphalus aonidum Linn.). — A circular dark
brown scale with a grey nipple in a reddish brown ring. Occurs on
Araucaria, citrus, oleander, begonia, and rubber plant.

CLASSIFICATION AND DESCRIPTION OF COMMON iNbJsCib ijJ5

Greenhouse Orthezia {Orthezia insignis Dougl,). — An ochreous to
green insect, covered with plates of waxy secretion. Occurs on many
plants (Fig. 8i).

Aspidistra Scale {Hemichionaspis aspidistm Signoret). — Female
scale Ko inch long; oviparous; light or dark brown with exuviae
brighter; thin and delicate; somewhat oyster-shell shaped. Male

Fig. 87.-

-Front of head and cauda of aphids: a, Microsiphum cralagi; b, Myzus
(apterous); c, Myzus (alate); d, Phorodon.

scale white, 3-ridged, slender, edges parallel. Occurs on Boston fern,
aspidistra, orange, orchids, Davallia (Figs. 85 and 86).

Control. — On indoor plants for Mealy Bugs use Black Leaf 40
(i to 400) and soap (4 lb. to 50 gal.); for Hard and Soft Scales use
whale-oil soap (i lb. to 2 gal.) or a dilution of some good miscible oil to
which Black Leaf 40 has been added.

136 ECONOMIC ENTOMOLOGY

Spray with lime-sulphur, whale-oil soap, kerosene emulsions,
miscible oils or whitewash when outdoor plants are infested.

APHIDID^ (APHIDS OR PLANT-LICE)

Chief Economic Gener\ (Figs. 86-94)

\. Front wings with four oblique veins; antennae generally 6-segmented.
B. Media of fore wings twice forked (except Lachnus in part).
C. Antennas of winged female s-segmented. — Sipha.
CC. Antennas of winged female 6-segmented.

D. Cornicles mammiform; filament of sixth segment of
antennae not developed.

E. Fore wing with stigmal shading appearing as the
stigma, extending to tip of wing. Large aphids
occurring commonly on Quercus, Tilia, and Plalanus.
— Longistigma.
EE. Venation normal, except in Lachnus where media is
sometimes unbranched or only once forked. Occur-
ring usually on conifers, never on Tilia or Platanus.
F. Flocculent species. Never on conifers. — Phyl-

lapliis.
FF. Not conspicuously flocculent as in F. Occur-
ring on conifers. — Lachnus.
DD. Cornicles variously shaped, seldom mammiform but if so
the filament of sixth antennal segment developed.

E. Large aphids with cornicles usually vasiform, body
and appendages hirsute. Occurring on Populus and
Salix. — Pterocomma.
EE. Not as above.

F. Cornicles short or wanting, usually tuberculate;
Cauda bluntly rounded or knobbed.
G. Cornicles appear as mere rings; wings held
horizontal when at rest. — Monellia.
GG. Cornicles usually distinct; wings held
slanting or roof-shaped over back when at
rest.
H. Body and appendages hirsute in
which respect it approaches Ptero-
comma but smaller and mostly leaf-
feeders; hairs not knobbed; antennae
noticeably shorter than body; gre-
garious on host. — Chaitophorus.
HH. Body not conspicuously hirsute;
antennae varying in length often

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS I37

noticeably longer than body; hairs on
antennae and body usually knobbed;
most species living solitary or scat-
tered on host. — Callipterini (includes
Myzocallis, Calliptcriis, Euceraphis
et al.).'

Fig. 88. — Types of cornicles among the aphids. Beginning from left,
Aphis avence, A. brassicce, A. gossypii, Chailophorus ncgundinis, Hyadaphis sp.,
Liosotnaphis sp.

FF. Cornicles short to very long but not tuberculate ;
Cauda not globular or knobbed.
G. First antennal segment gibbous on inner
side.

Fig. 89. — Front of head and cauda of two aphids: a, Rho palosi phiim; b, Aphis.

H. Frontal or antennal tubercles with
a prominent tooth-like projection
on inner side; cauda tapering. —
Phorodon.
' See Can. Enl., Vol. 42, No. 8.

138

ECONOMIC ENTOMOLOGY

Fig.
aphids:
daphis.

HH. Frontal tubercles without the promi-
nent tooth-like projection; cauda
more or less sickle shaped. — Myzus.
GG. First antenna! segment not conspicuously
gibbous on inner side.
H. Head with distinct and more or less
prominent frontal tubercles.
I. Cornicles clavate; antennae sel-
dom longer than body; cauda
tapering and knobbed. — Rhopalo-
siphum.
II. Cornicles cylindrical or incon-
spicuously swollen; antennae usu-
ally longer than body; cauda
ensiform. — Macrosiphum.
HH. Head with frontal tubercles absent or
slight.
I. Cornicles distinctly clavate. —

Siphocoryne (Hyadaphis),
II. Cornicles usually cylindrical and
of moderate length; if clavate
they are only slightly swollen
and quite small.
J. Cornicles very short, much
shorter than cauda, slightly
swollen; beak short; antenna:
shorter than body. — Hyalop-
terus.
J J. Not as above, i.e., cornicles
moderately long, usually
longer than cauda, cylindri-
cal; antennae usually as long
as or only slightly shorter
than body. — Aphis.
BB. Media of fore wings once forked or simple.
C. Media simple.

D. Hind wings with two oblique veins. — Pemphigus.
DD. Hind wings with but one oblique vein.

E. Antennae 6-segmented. — Tetraneura.
EE. Antennae s-segmented. — Hamamelistes.
EEE. Antennae 3-segmented. — Hormaphis.
CC. Media once forked.

D. Cornicles present, an Aphis-like species. — Toxoplera.
DD. Cornicles vestigial or wanting.

E. Hind wings with two oblique veins. — Eriosoma.
EE. Hind wings with one oblique vein. — Colopha.

90. — Front of head of
a, Chaitophorus; b, Hya-

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS I39

A A. Front wings with three oblique veins, the media simple (unbranched),
radial sector merged with margin of stigma; antennae never more than 5-
segmented.
B. Antennae s-segmented; wings at rest folded upright; galls on conifers.
— Chermes.
BB. Antennae 3- or 4-segmented; wings at rest flat on back; galls on grape,
hickory, etc., never on conifers. — Phylloxera.

Sc*RtM*Cu* 1st A 5c

Sc^R*M*Cu*lstA Sc

Fig. 91. — Venation of Macro-
siphum. (After Patch.)

Fig. 92. — Venation of Toxoptera.
(After Patch.)

Plant-lice or Aphids are gregarious sucking insects, often abundant
on many varieties of plants, and doing much injury. Three forms
occur: i. sedentary wingless viviparous agamic females, 2. migra-
tory winged viviparous agamic females, 3. sexual males and females
— the females oviparous and wingless and the males winged or wingless.

Sc*R-'M*CuflstA Sc

5c*R^M*Cu*lstA -

4 —5c

Fig. 93. — Venation of Telra-
netira. (After Patch.)

Fig. 94. — Venation of Chermes.
(After Patch.)

Reproduction among the aphids may be represented diagrammatic-
ally as follows:

O— P— P— P— P— P— P— P— P(^ ^0

9

= P = P_P— p_P— p/ \o

9
where represents the overwintering egg, P the viviparous agamic

140

ECONOMIC ENTOMOLOGY

wingless form, and =P= the viviparous agamic winged form, and
cf and 9 the sexual forms (Fig. 95).

In general, plant-lice are soft-bodied and green, sometimes brown
or black. The winged forms have four delicate wings with a few simple
veins — the front pair much larger than the hind pair. The sucking
beak is 3-jointed; the legs and antennae are long and the eyes promi-
nent. In autumn the sexual females deposit eggs that hatch in the
spring into females which are often termed "stem-mothers." These
produce living females which in turn produce living females, and so on
for several generations. As each female produces several young, and

these mature in a short time, reproduction is
very rapid. When autumn approaches and
food supply becomes scarce a brood of winged
males and wingless females is produced.
The females produce the winter eggs. Some-
times agamic females hibernate.

There are many species of plant-lice,
some feeding on one variety of plant, but
many are capable of feeding on two or more
varieties. Some feed for a time on one host
plant, then migrate to another for the sum-
mer, finally returning to the first one in
autumn. Some produce abnormal growths
called galls, such as the grape phylloxera
gall, the cockscomb gall on the elm, the
Cottonwood gall, the poplar gall, etc.

Most plant-lice excrete a sweet liquid called "honey-dew," which
is attractive to ants, bees, wasps and other insects. On account of
this honey-dew aphids are often attended by ants who guard them.
Forbes has shown that the little brown ant {Lasius niger) has domesti-
cated the Corn Root Aphis, which is cared for and controlled in all
stages of its development. (Consult Bull, no, 112, 276 and Farmers'
Bull. 804, U. S. Dept. Agr., and Bulletins by Parrott, Patch, Forbes,
Herrick and Matheson.)

Fecundity. — Regarding the powers of reproduction of aphids Web-
ster and Phillips (Bull, no, U. S. Bur. of Entom.) cite the estimates of
Huxley and Buckton. The former estimated that the tenth genera-
lion alone of a single Rose Aphis, were there no deaths, would contain

Fig. 95. — An apterous vivi-
parous female aphid.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 141

more substance than 500 million stout men; the latter computed that
in 300 days, or 15 generations of 20 each, there would be 20"" indi-
viduals, equal in weight to 1,638,400,000 men, supposing that 1000
aphids weigh i grain and i man weighs 2,000,000 grains. Another
computer makes the possible number of individuals very much higher,
viz., 210^^. It is believed that in the case of the Spring Grain Aphis
or "Green Bug" (Toxoptera graminum) reproduction would not fall
short of the figures given above as the average number of young pro-
duced in Indiana by each viviparous female for 1907-8-9 was 28.2.
It is conceivable, therefore, how this pest is able to devastate vast
areas of grain fields within a few weeks.

Professor Forbes of Illinois (Bulletin 130) also computes the
fecundity of the Corn Root Aphis on the basis of a generation of 12
to 15 young in 2 weeks. If all the progeny lived and multiplied at
this rate for a season they would reach 9,500,000,000.

In the case of the Green Apple Aphis {Aphis pomi) A. C. Baker
reports the average reproduction per insect for the entire season as
about 40. As the stem-mother becomes mature about May ist in Vir-
ginia, and there are from 9 to 17 generations, or an average of 13, re-
production is very rapid. The potential number of green apple aphids
in September from a single stem-mother would be 40^^ = 670,088,-
640,000,000,000,000.

J. J. Davis reports for the Oat Aphis {Aphis avence) 15 generations
for Indiana with an average of 30 young for each female. The progeny
of one stem-mother at the end of the season would be 30^^.

The same writer gives for the Pea Aphis {Macrosiphum pisi) the
average number of young borne by female of 16 consecutive genera-
tions as 65. The progeny of a stem-mother at the end of the season
would in this case be 65^^.

Natural Enemies. — ^Lady-bird beetles, syrphid maggots, lace-wing
larvae, many parasitic hymenoptera, nymphs of tree-crickets, harvest-
spiders, birds.

Control. — Spray with kerosene emulsion, whale-oil soap, tobacco
extract, etc.

Chief Economic Species
COMMON CEREAL AND FARM CROP APHIDS

Apple Bud or Oat Aphis {Aphis avencB Fab.). — Sometimes called
the European Grain Aphis; is often injurious to apple buds and appears

142 ECONOMIC ENTOMOLOGY

before the other apple aphids. Stem-mothers appear early in May and
are yellowish-green with three dark lines on back; progeny winged and
blackish; migrate to grains and grasses in the second and third genera-
tions, winged and wingless generations. Migrate back to apple in
September where mating occurs. Males produced on the secondary
host and females on the primary host. Beak short and stout; thoracic
shield dark; cornicles short and flanged; cornicles, antennae and feet
black.

Clover Aphis {Aphis baker i Cowan). — Sometimes attacks the apple
in the middle West. Eggs are laid on the apple, the pink stem-mothers
appear early and give rise to green winged and wingless forms. The
former migrate to clovers and give rise to several wingless generations.
In late autumn the winged forms fly back to the apple and hawthorn
where the eggs are laid. Cornicles are short.

Com Leaf Aphis {Aphis maidis Fitch).- — Bluish-green, with black
legs, antennae and cornicles; a row of black dots on each side of
back.

Com Root Aphis {Aphis maidi-radicis Forb.). — Bluish-green lice on
corn roots; attended by brown ant {Lasius niger).

Spring Grain Aphis or Green Bug {Toxoptera graminum Rond.). —
Infests cereals in spring; wingless form yellowish-green, with faint dark
line along back; eyes black. Winged form larger, with darker thorax.
Migrates to other regions and to grasses. Parasitized by Lysiphlebus
tritici.

Western Grain Aphis {Brachycolus tritici Gillette). — Is injurious
to winter wheat in Montana.

English Grain Aphis {M acrosiphum granarium Kir by) . — Occurs on
wheat, barley and the grasses, Agrostis, Bromus, Dactylis, Poa and
Phleum and Cat-tail, widely distributed in the U. S.

COMMON FRUIT APHIDS

Apple Bud or Oat Aphis {Aphis avencB Fab.). — See above.

Green Apple Aphis {Aphis mali Fab. = A. pomi DeG.). — This
aphis collects usually on the tips of tender shoots, on the under surface
of the leaves, and when abundant attacks the developing fruit.
Winters on twigs as black shining eggs which hatch just before leaf
buds open; Jf 2 irich long, pear-shaped; bright green; black, slender

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 43

cornicles; inhabits the apple throughout the season; winged females
occur during summer. Causes curUng of the leaves to some extent,
those of young trees suffering most. Several (10-15) generations

Fig. 96. — Green apple aphis {Aphis pomi): a, alate or winged form; b, apterous
or wingless form; c, oviparous female; d, male; e, antenna of winged form.

in a season, and each generation shorter than 3 weeks; each mother
produces about 70 young (Fig. 96).

Rosy Apple Aphis {Aphis sorbi Kalt. = A. malijolm Fitch = A.
Pyri Boyer).— This shade-loving aphis collects around the flower buds,
the developing fruits and on the under side of the leaves. It causes
nearly all the curling of the leaves and the "cluster-apples." Larger
than preceding; J^ inch long. Wingless females blue; honey-tubes

144 ECONOMIC ENTOMOLOGY

yellow tipped with black, long and tapering; body covered with a
powdery substance. Winged females with black thorax and red ab-
domen, honey-tubes long and black. Two small tubercles at end of
abdomen; the late winged forms are migrants and have a black patch
on abdomen, black bands across last segments of abdomen, and black
spots on sides. Egg-laying females lemon-yellow, mate with migrant
winged males. In this species also the males are produced on the
secondary and the females on the primary host. After the third
summer agamic generation this species deserts the apple for the
plantain, but returns in autumn. (Consult ''Apple Tree Insects of
Maine," Circ. 31, Bur. Ent., U. S. Dept. Agr.)

Sweet Cherry Aphis {Myzus cerasi Fab.). — Eggs oval and black,
laid around the buds and on bark of twigs and branches, hatching in
late April. Stem mother globose and glossy black. First brood
wingless viviparous, later broods winged and wingless viviparous; the
winged form with head, thorax, cornicles and cauda black, and abdomen
dark green to dark brown migrate to Lepidium where several broods of
dark brown, wingless viviparous forms and darker winged forms are
produced. The latter return to cherry when they and other resident
winged forms produce viviparous females which are fertilized by
migrant winged males from Lepidium. No males are produced on
the cherry. Six to 14 generation are produced during the season in
the Niagara district. Controlled most successfully in early spring,
just before the buds burst, by spraying with lime sulphur and Black
Leaf 40 (Ross, 48//? Rep. Out. Ent. Soc, 1917).

Clover Aphis (Aphis bakeri Cowan). — See above.

Green Peach Aphis {Myzus persicce Sulz). — This general feeder is our
most common greenhouse species. Under glass it reproduces vivi-
parously from year to year. At first the young lice are pink, but next
generation is bright green. Migration in third generation to garden
crops (where it has been known as Rhopalosiphum diantki Schr.)
returning in autumn to peach.

Currant Plant-louse {Myzus ribis L.).- — A small yellowish plant-
louse causing a curling and bhstering of the leaves of currants with
red discoloration of the upper surface. Wingless female light green
and mottled; body covered with capitate hairs, and with two rows
of spots on mid-dorsal surface. Winged forms darker and abdomen
crossed by several bands. Migrates to Stachys and Galeopsis (Gillette).

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 45

Hop Plant-louse {Phorodon humuli Schrank). — Migrates from plums
to hop in the third generation; yellowish-green, with a prominent
tubercle on head at base of each antenna, and another smaller tubercle
on the base of each antenna.

Apple Woolly Aphis {Schizoneura (= Eriosoma), lanigera Haus,
americana Riley in part). — (Consult Bull. 256, Maine Agr. Expt. Stn.,

Fig. 97. — Forms of the woolly apple aphis: A, winged viviparous female;
B, stem-mother; D, wingless viviparous female, summer form; E, male; F, pupa
of fall migrant; G, oviparous female. All much enlarged. {After Baker, U. S. Bur.
Ent.)

1916.) This native woolly aphis is frequently injurious to many vari-
eties of apple trees, causing deformations both on the stems and leaves
and on the roots. It occurs also on pear, hawthorn and mountain
ash, and passes part of its hfe on the elm. The injury to the roots
consists in the formation of hard fibrous enlargements resembling
knots or clubs, often causing the death of the affected part. Nursery

146 ECONOMIC ENTOMOLOGY

stock is liable to infestation and severe injury. The injury to the
branches is not so serious, but in cases of severe infestation it causes
stunted growth and yellowing of the leaves. Colonies often collect
at the axils of leaves, on water-sprouts, and at abrasions and wounds.

The common form seen on roots and limbs is wingless, }-{o inch long,
reddish-brown, and covered with a woolly waxy excretion (Fig. 97).

The life-history of the trunk forms is as follows:

Some winter near the base of the apple tree as immature nymphs;
but those in the elm as eggs in crevices of the bark. The hibernating
nymphs on the apple migrate to the branches in early spring, and a
succession of parthenogenetic generations of apterous viviparous
females appears throughout the season. From the eggs on the elm
hatch out apterous viviparous stem-mothers in early spring about May
15 th, the second generation is also apterous viviparous, but the third is
winged and migrates to the apple, hawthorn and mountain ash where
three generations are developed, two being apterous, and the third
part apterous and part winged. The winged form migrates back
to the elm, and produces the wingless sexual forms. Each female
lays one large yellow egg which winters on the tree. The wingless
forms remaining on the apple give rise to another generation which
winters over as immature nymphs.

The injury to the elm leaves is characteristic — the formation of
terminal leaf clusters or rosettes. S. americana produces leaf-curl.

The winged forms are nearly black, the abdomen being rusty brown,
the wings are clear and the antennae have annulations and are 6-jointed.
The sexual forms are wingless, beakless, smaller than the agamic
forms; the female 3^^o inch long, reddish-yellow, is larger than the
olive-yellow male; the antennae are 5-jointed, and without annulations
as in other apterous forms. The root colonies ordinarily remain
underground throughout the year, and do less injury northward.

Parasites. — Aphelinus mali, a chalcid; Pipiza radicum, a syrphid;
lady-bird beetles.

Control. — Spray thoroughly the aerial forms with kerosene emulsion,
soap solution or tobacco decoction; dip roots of suspected nursery
stock in same solution or fumigate with HCN; add tobacco dust
to the soil.

Black Peach Aphis {Aphis persicce-niger Er. Sm.). — Black; lives

L.XAJ3t3lJ?J(JAiiUJN AND UKSCKiFTiUJN UH LUMMUJN liNbiLCTb

147

on roots, twigs and leaves. No migration. Of no economic importance
in Ontario (Fig. 98).

Mealy Plum Louse {Hyalopterus arundinis Fab.). — Has long narrow
light green body with three longitudinal stripes; covered with a mealy
powder; honey-tubes short and thick; winged females migrate in June
to grasses and cat-tail and return in autumn.

Variable Currant Aphis {Aphis varians Patch). — Infests currants,
gooseberries and flowering currants, causing curling of the leaves.
The winged summer forms migrate to some unknown host, and return

Fig. 98. — Black peach aphis (winged female). {After Quainlance.)

in the fall. The eggs are deposited on the twigs. The stem-mother
is purplish-green with white honey-tubes. The winged form has a
black head and body, with a dark green abdomen marked with black,
while the wingless form is dark green, tan or dark brown.

Green Gooseberry Aphis {Aphis sanborni Patch) .^ — Green; honey-
tubes white.

Grape Phylloxera {Phylloxera vitifolice Fitch = vastatrix Planchoa).
—Four forms are recognized: (i) wingless leaf-gall form; (2) wingless
root form; (3) winged form; (4) sexual form.

I. Adult leaf -gall form is a wingless female, plump, orange-yellow.
Fills gall with many yellow eggs which hatch in 3 days into females.
Several generations during summer. The feeding puncture stimulates
the growth of the leaf tissue so that a hollow gall is produced, opening
on the upper surface.

148 ECONOMIC ENTOMOLOGY

2. Root form similar to that on leaf; often derived from leaf form ;
several generations in a season; yellowish and wingless, and forms
nodules which break down and decay, often destroying the root.
Yellowish oval eggs are laid on the roots. Larvae moult three times.
Leaf-galls are most common on American grapes while root-galls are
most common on European grapes.

3. Some of the root forms in late summer develop elongate long-
legged winged females that fly to neighboring vines and lay 2-4 eggs
beneath loose bark.

4. These eggs are of two sizes — the smaller producing males, the
larger sexual females. These are wingless and minute. Each female
lays one large egg from which hatch the following spring the leaf and
root forms. Not destructive on sandy soils.

Control. — Spray in early spring with lime sulphur; use American
varieties as stock.

COMMON GARDEN APHIDS

Cabbage or Turnip Plant-louse {Aphis brasskce'L.). — Often abun-
dant on the under surface of leaves of cabbages and turnips, and very
destructive in warm dry weather. A greenish, soft, pear-shaped insect
covered with a whitish bloom. Mature forms have black head and
eyes and dark cornicles; nymphs are pale green with black legs and
antennae. Parasite, Aphidius rapa, a braconid.

Aphis pseudobrassicae Davis. — Also occurs on turnip, radish, cab-
bage, rape, mustard, etc., and is often mistaken for A. brassicce.

Melon Plant-louse (Aphis gossypH Glov.). — Occurs on the under
surfaces of the leaves of melon, cucumber, squash etc., and also on other
crops and weeds. Winter eggs have been found on purslane and straw-
berry. A blackish-green insect. Apterous females with legs and
antennae whitish, cornicles black and short; winged forms with a row of
black spots on sides of abdomen, and spots on head and thorax.

Bean Aphis [Aphis rumicis L.). — Occurs on the tips of horse and
broad beans at time of flowering. When the lice are abundant the
plants assume a sooty sticky appearance. Also on apple, dahlia, dock,
shepherd's purse, pigweed, snowball and burning bush. This aphis is
slaty blue or black, with white bands on the legs and often with waxy
tufts. Called also the "black fly," "colHer" and "black dolphin."

Strawberry Root Louse {Aphis forbesi Weed). — Bluish-green, on
roots of strawberry; occurs also on leaves. Eggs laid on stems and

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 49

leaves. Ants carry lice to roots. Of no economic importance in
Ontario.

Pea Plant-louse {Macrosiphum pisi Kalt.). — Green; eyes red; legs
long; migrates in August to clover fields where eggs are laid and first
spring generation feeds. Parasites — A phidiusjietcheri Ash., Megorismus
fletcheri Crwd., a chalcid.

Potato Plant-louse {Macrosiphum solanifoUi Ashmead). — Green or
pink; migrates to the rose, where winter is spent. Feeds on a large
number of plants.

Green Rose Aphis {Macrosiphum rosce Linn.). — A large pale green
aphis with dark antenna? and the cornicles long and black. Occurs on
roses.

Black Chrysanthemum Aphis {Macrosiphum sanborni Gill.). — •
Occurs on chrysanthemums in greenhouses. A brownish-black pyri-
form plant-louse.

COMMON SHADE AND FOREST TREE APHIDS

Negundo Plant-louse {Chaitophorus negundinis Thos.). — A serious
pest of the ash-leaved or Manitoba maple in the West. Infested trees
soon become covered with honey-dew in which a sooty fungus develops.

Woolly Apple Aphis {Schizoneura lanigcra).- — See above.

Poplar Leaf Gall Louse {Pemphigus populicaulis Fitch).— Pro-
duces a deformity at the junction of petiole and blade of cottonwood
and aspen.

Alder Blight {Pemphigus tessellatus Fitch). — A Woolly aphid, occurs
on branches of alder. Winged forms migrate to the maple.

Beech Tree Blight {Pemphigus imbricaior Fitch).- — A similar form on
the twigs and leaves of beech.

Sitka Spruce Gall Aphis {Chermes cooleyi Gillette), Western Hem-
lock Woolly Aphis {Chermes funilectis Dreyfus), Sitka Spruce Green
Aphis {Aphis abietina Walk.). — Are important economic forms on the
Pacific Coast of British Columbia.

Spruce Gall Aphis {Chermes abietis Choi). ^Abundant locally on
White and Norway spruces, producing pine-apple-like galls at base of
terminal shoots. Each gall, ^ inch long, contains about 50 cells each
holding from 8 to 12 nymphs. The life-cycle is briefly as follows:

"Galls open about mid- August and fully grown pupae emerge and
moult within a few hours becoming the winged form which deposits a

150 ECONOMIC ENTOMOLOGY

cluster of 40 to 50 yellow eggs on a spruce needle. The eggs are
extruded from the abdomen but the parent Chermes remains over them
until dislodged after her death by wind or rain. The winged form often
oviposits near the gall from which it emerges. A different species of
host plant is never sought by this Chermes. In about two weeks the
young "stem-mothers" hatch from these eggs and seek a protecting
crevice in the surface of the spruce bud where they can spend the winter.
These wingless forms develop in the spring and become full grown about
the last of May when they lay a cluster of 140 or more eggs. From
these eggs hatch the young that inhabit the gall and are known as the
"gall generation" with which we started the cycle" (Patch).

Spruce Gall Aphis {Chermes similis Gill.). — (Consult Bull. 173,
Maine Agr. Exp. Stn.). Abundant locally on black, red, white and
Norway spruces, producing loose terminal galls and scraggly deformed
twigs. The galls open about July ist and the winged flocculent mi-
grants oviposit on spruce.

Control. — Spray in early spring while trees are dormant with whale-
oil soap (i lb. to 2 gal. water). Black Leaf 40 (i to 800) added to
soap (i lb. to 4 gal. water).

Pine Bark Aphis {Chermes piniccrticis Fitch). — A common enemy
of cultivated pines, appearing as flocculent white masses upon the green
bark of the more tender parts.

Control. — Spray in late April or May with fish-oil soap or kerosene
emulsion.

DOUBLE-HOST APHIDS

Following is a partial list of double-host Aphids:

Chermes abieticolens on spruce = Chermes pinifoliae on white pine.
Pemphigus tesselatus Fitch on alder = Pemphigus acerifoliae Riley on maple.
Pemphigus balsamiferte on cottonwood = Pemphigus betae on beets.

Eriosoma pyricola on pear = Eriosoma pyricola on elm.

Eriosoma lanigera on apple = Eriosoma americana in part on elm.

Eriosoma americana on plum = Eriosoma americana on Juneberry.

Eriosoma ulmi on English elm = Eriosoma fodiens on currant.

Hyalopterus arundinis on plum = H. arundinis on reed grass, cat-tail.

Phorodon humuli on plum = P. humuli on hop.

Aphis avenae on apple = A. avenae on oats, cat-tail, etc.

Aphis sorbi on apple = A. sorbi on plantain.

Aphis pruni on plum = Aphis cardui on thistle.

Aphis peril on oleander = A. lutescens on milkweed.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 151

Aphis bakeri on apple and hawthorn = Aphis bakeri on clover.
Aphis brevis on apple and hawthorn = Aphis brevis on clover.
Aphis euonymi on snowball and burning = Aphis rumicis on bean and dahlia.

bush
Macrosiphum illinoiensis on Viburnum = M. illinoiensis on grape.

prunifoliae
Macrosiphum solanifolii on rose = M. solanifolii on potato.

Macrosiphum granarium on grains, rose, = M. granarium on cat-tail.

etc.
Aphis prunorum Dob. on plum, Ribes = Rhopalosiphum nymphaeas on Nym-

phaea, Alisma, Sagittaria, Typha.
Rhopalosiphum ribis on Ribes = R. lactucae on Sonchus.

Rhopalosiphum capreae on willow = R. capreae on Umbelliferae.

Myzus ribis on Ribes = M. galeopsidis on Galeopsis, Stachys

and Leonurus.
Myzus cerasi on cherry = M. cerasi on Lepidium.

Myzus persicas on peach = Rhopalosiphum dianthi on garden

plants.
Rhopalosiphum pastinaceae on Lonicera = R. pastinaceae on Pastinaca.
Hormaphis hamamelidis Fitch on witch = Hormaphis hamamelidis on birch.

hazel
Hamamehstes spinosus Shimer on witch = Hamamelistes spinosus Shimer on birch.

hazel
Tetraneura graminis on Ulmus = T. graminis on Leersia.

Thecabius populiconduplifolius on = T. caHfornicus on Ranunculus.

poplar
Chermes floccus on white pine = Chermes floccus on Red and Black

spruce.
Chermes cooleyi on Blue and Engelmann = Chermes cooleyi on Douglas fir.

spruces

Aleyrodid^ (White Flies)

White Fly (Aleyrodes vaporariorum. Westw.). — (Consult Bull. 140,
Conn. Agr. Exp. Stn.) Injurious both in adult and nymph stages
sucking the juices from the under surfaces of the leaves.

Often abundant in greenhouses, and difficult to control.

Adult. — Wings pure white, covered with minute particles of wax;
body yellow, Ke inch long; antennae 6-jointed; beak 3-jointed; tarsus
2-jointed; eyes brown, in two pairs.

^Sg^- — Elongate-oval, ^-foo inch long, laid on the leaves; light
green or white to dark; hatch in 1 1-14 days. Unfertihzed eggs produce
males only; each female usually lays several dozen eggs.

152 ECONOMIC ENTOMOLOGY

Nymphs. — Three-one-hundredths inch long, yellowish when full
grown; long waxen rods on back of "pupa." Life-cycle about 5 weeks.

Control. — Fumigate at night with hydrocyanic acid gas Q/^ oz.
potassium or sodium cyanide, i fi. oz. sulphuric acid, 3 ii. oz. water,
for every 1000 cubic feet of space); spray or wash repeatedly infested
leaves with whale-oil soap {i^^ oz. to i gal. water).

Citrus White Fly {Dialeurodes citri Ashm. = A. citri Riley &
Howard). — A most serious pest of oranges and other citrous plants of
the South. (Consult Tech. Ser. No. 12, Pt. V and No. 27, Bur. Ent.,
U. S. Dept. Agr.)

PsYLLiD^. (Jumping Plant-lice)

Pear Psylla (Psylla pyricola Fuerst). — A European pest introduced
about 1832, and now widely distributed over the Eastern states and
Canada.

Adult. — A dark reddish-brown bug, Hq inch long; abdomen with
black bands; wings clear with dark veins and laid roof-Hke over the body;
when disturbed it hops and flies away. Eyes bronzy; hibernates on
trunk in crevices, etc.; 4-5 generations each year.

Eggs. — Orange-yellow, minute; 3^^ g irich long, pear-shaped; depos-
ited in crevices of bark or along midrib of leaf; hatch in 2-3 weeks.

Nymphs. — Broadly oval, flattened, yellowish bodies with crimson
eyes; later reddish with black markings and conspicuous black wing
pads; secrete honey dew; 4-5 moults.

Natural Enemies. — ^Lady-birds, protracted periods of wet cold
weather in spring, and long spells of hot dry weather in summer.

Control. — Clean cultivation; bark scraped; spraying with Black
Leaf 40 ( I pint in 100 gal. water) during warm days in early spring,
late fall or after blossoming; spraying with lime-sulphur just before
opening of blossoms.

Bramble Flea -louse {Trioza tripundata Fitch). — Occurs on black-
berry, causing curling of the leaves and dwarfing of the shoots.

Adult. — A small reddish-brown, jumping plant-louse, 3^^ inch long;
wings with three yellowish-brown bands. October- May or June.

Eggs. — ^Light yellow, deposited in June- July on blackberry.

Nymphs. — Mature in September-October; young nearly pure white'
to a greenish white; older nymphs yellowish. ' '

classification and description of common insects 1 53
Cercopid^ (Froghoppers or Spittle Insects)

(Consult Bull. 254, Maine Agr. Expt. Station)

These insects commonly occur in meadows and are often conspicuous
by the large number of frothy masses resembling spittle on the leaves
of grass, clover and weeds. The injury done is difficult to estimate but
it must be considerable in the aggregate. Philccnus sptimarius and P.
lineatus are common in meadows, and Aphrophora parallela Say on
pines.

Meadow Froghopper {Philcenus spumarius Linn.).^ — This insect
feeds on oats and a wide range of plants, many of them weeds, but
not on grasses. The injury is apparent in the formation of withered
or dwarfed seeds.

Adult. — Body elongate-oval, head bluntly angular, wing-covers
extending well beyond the end of abdomen. Color pale grey to black,
and the markings quite irregular in form.

Eggs. — Elongate-elliptical, one side straight, the other curved.
Shell tough and hard; hibernate in dead stems or leaves in
meadows.

Nymphs. — Almost colorless; three instars; antennae 9-jointed. The
viscid frothy masses excreted from anal opening and certain lateral
glands on seventh and eighth abdominal segments. The masses are
believed to be protective.

Control. — Rotation of crops; early mowing to kill the nymphs;
burning the surface dead grass to kill the eggs.

Grass-feeding Froghopper {Philcenus lineatus L.).- — This spittle
insect is found almost exclusively on grasses, especially on timothy
and red top, and undoubtedly does considerable injury. It causes
withering of the stems and blasting of the heads.

Adult. — Distinguished from P. spumarius by its longer head, and
narrowed body with more nearly parallel sides. Front of head rounded-
angular and as wide as thorax. Color grey with a whitish costal
margin and a blackish border line.

Eggs. — Hibernate; hatch late in spring.

Nymphs,— Three or more instars; mature in July.

154

ECONOMIC ENTOMOLOGY

Family Cicadellid^ (Leaf-hoppers)

(Consult BuU. io8, Bur. Ent.

U.S. Dept. Agr. and Bull.
Exp. Stn.)

238, 248, Maine Agr.

The Leaf-hoppers are divided into four fairly distinct sub-families,
separated by means of the venation of the wings and by the head parts:
(i) BythoscopifKB occurring mainly on trees or shrubs, and including
Idiocerus alternatus and the Clover Leaf -hopper (Fig. 99); (2) Cica-
dellincB, including the Sharpshooter {Oncometopia undata) and Dracula-
cephala mollipes occurring in grass land; (3) Jassince, including the
Shovel-nosed Leaf-hopper (Dorycephalus platyrhynchus) on wild rye

Fig. 99. — The clover leaf-hopper (Agallia sanguinolenta) : a, adult; b, nymph,
side view; c, iiymph, dorsal view; d, face; e, elytron; /, female genitalia; g, male
genitalia. All enlarged. {After Osborn and Ball.)

(Elymus), the Inimical Leaf-hopper (Deltocephalus inimicus) on blue
grass, the Destructive Leaf-hopper {Athysanus exitiosus) in grain fields,
and the Six-spotted Leaf -hopper (Cicadula 6-notata) in oat fields;
and (4) Typhlocybina including the Apple Leaf-hopper {Empoasca
mali) the Rose Leaf-hopper (Empoa rosce) and the Grape Leaf-hopper
{Erythroneura comes).

The presence of leaf -hoppers in very large numbers in meadows and
pastures in late summer indicates that considerable injury is being done,
and that they must be reckoned among insects of economic importance.

Six-spotted Leaf -hopper (Cicadula 6-notata Fallen).— A small yellow
form 4 mm. long with six black dots on the vertex and a double series
of black arcs on the front. Occurs on oats, timothy, etc., producing
spots on the leaves, whitish at first, then turning to brown or black.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 55

Black Apple Leaf -hopper (Idiocerus fitchi Van D.). — A common pest
in the AnnapoUs Valley but the injury is small. The eggs are laid in
August and hatch from May 22d to June 13th. The duration of
nymphal stage (5 moults) is about 50 days.

Beet Leaf -hopper {Eutettix tenella Baker). — (Consult Bull. 66, Pt.
IV, U. S. Bur. Ent.; Utah Bull. 155.) This native leaf-hopper causes
the "curly-leaf" disease of sugar beets in the Western States and is
therefore responsible for much loss. Found also on A triplex, Russian
thistle, Sea-blite and Sarcobatus. One brood a year.

Adult. — Small, 3^^ inch long, pale yellowish-green to white, often
straw-colored. June-August. Hibernates.

Eggs.— Vale greenish-white, elongated, tapering at the end; inserted
in the stems or large veins of leaf; hatch in about 2 weeks.

Nymphs.- — White at first, becoming like the adult but wingless.
Active. Duration 20-25 days. July-September.

Grape Leaf -hopper {Erythroneura comes Say).— (See Bull. 215,
Cornell Ag. Exp. St., 1904.) This bug is a very common pest in
vineyards, and occasionally does considerable injury to the leaves which
curl and turn brown. During the summer the nymphs feed on the
under surface of the leaves and give them an unnatural spotted ap-
pearance. The adults, mature in August, also do much harm. Feeds
also on Virginia Creeper, Strawberry, etc.

Adult.- — One-eighth inch long; wings and back variably marked
with yellow and red. Hibernates in nearby grass and wood-lands,
and emerges about May ist.

Eggs. — Three-one-hundredths inch long, semi-transparent, slightly
curved and faintly yellow; deposited in June beneath the lower skin
of grape leaves; hatch in 9-14 days.

Nymphs. — ^Light yellowish-green with lemon-yellowish stripes on
each side of the body; pass through 5 stages in 20-23 days; mature in
July-August.

Control. — Spray thoroughly with Black Leaf 40, tobacco extract or
kerosene emulsion when young nymphs appear; clean culture.

Apple Leaf-hopper {Empoasca mali Le Baron). — (Consult Bull.
io8. Bur. Ent., U. S. Dept. of Agriculture, and Journ. Econ. Entomology,
Vol. 2, p. 54; Vol. II, pp. 144-148.) Occurs also on beans, alfalfa,
clover, potatoes, currants and gooseberries.

Adult. — Slender and cylindrical, 3-^ inch long; brilliant grass-green;

156 ECONOMIC ENTOMOLOGY

white lines and dots between the eyes; a series of six whitish spots
on front margin of prothorax, two whitish hnes on mesothorax form-
ing a letter H; three dots on scutellum; strongly convex above; front
rounded; wings thin and uniform, folded close about the body; legs
slender, hindmost larger; three or four generations each year. Adults
may live 14-30 days. Hibernates.

Eggs. — Autumn eggs laid in September under epidermis of apple,
summer eggs under epidermis of petioles of apple, clover, etc.; hya-
line, cylindrical.

Nymphs. — ^Light green; feed on under side of leaves causing white
spots, most injurious in May-June; five nymphal stages covering 22
days.

Control. — Spray in spring with a mixture of Black Leaf 40 and whale-
oil soap; collect adults by driving tanglefoot screens along the rows
in bush-fruits.

Rose Leaf -hopper {Empoa roses Linn.). — ^Leaves of rose bushes and
apple trees are often badly infested with the Rose Leaf-hopper, and all
stages of growth may be readily found. Eggs are laid in July, and
eggs are again laid in the fall beneath the bark of young wood of roses,
blackberry, and strawberry runners, where they stay over winter.
Migration from the roses occurs in June. Controlled by lime-sulphur
and Black Leaf 40 during the early nymph stages (Consult Bui. 148
Oregon Ag. Exp. St.)

ClCADID^

Periodical Cicada {Cicada septendecem Linn.). — (Consult Bull. 71,
Bur. Ent., U. S. Dept. of Agr.) Often called the Seventeen-year Locust.
Adults damage orchards and nurseries by making egg punctures in
the twigs.

Adult.— ^ne and one-fourth inches long, black; abdomen banded
with red; eyes red; veins red at base and along front margin; June;
duration about 30 days. Dwarf forms also occur.

Eggs. — Each female lays 300 to 500 eggs in punctures made by
ovipositor in twigs and stems; eggs hatch in 6 to 8 weeks.

Nymphs.- — Burrow in the ground, feeding on juices of roots and
humus of soil; moult probably 4 or 6 times at intervals of 2 to 4
years. In the spring of the seventeenth year they emerge and moult,
changing to adults. A race or sub-species having a 13-year period

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 57

occurs mainly in the South. Over twenty brooih have been recog-
nized and delimited.

Control. — Prune off affected twigs in July and burn before the hatch-
ing of the eggs; allow hogs the run of infested land during April and
May; avoid pruning the orchard
the year before a cicada year.

N atural Enemies. — A digger
wasp {Megastiziis speciosus), egg
parasites (cecidomyiid and chal-
cid); mites; the English sparrow,
catbird, robin, etc.

The Dog-day Harvest-fly
{Cicada tibicen Linn.). — Often oc-
curs but is not of much import-
ance economically. It is black
and green, and white powdered
underneath.

Membracid^ (Tree-hoppers)

Buffalo Tree-hopper {Ceresa
hiibalus Fab.). — (Consult Circ. 23,
Div. Ent., U. S. Dept. Agric.)
This bug is a common pest of or-
chards and shade trees feeding on
the sap of apple, maple, etc. It
injures the trees by making longi-
tudinal incisions in the bark, which
become points of weakness (Fig.
100).

Adult. — A grass-green bug, %
inch long, with the pronotum
greatly enlarged, and expanding
laterally into two horns and pos-
teriorly into a long point. July-
September.

Eggs. — Dirty-whitish, cylindrical, slightly curved, tapering toward
outer end; 3'! 6 i^^ch long. Laid in the bark in batches of 6-12 in two

Fig. 100. — Twigs showing egg punc-
tures of the Buffalo tree-hopper.

158

ECONOMIC ENTOMOLOGY

curved slits made by ovipositor. Egg-laying occurs in August and
September; hatching the following May and June.

Nymphs. — Covered along the centre of the back with numerous
forked or barbed spines or projections, a pair to each segment. General
feeders in or near orchards.

Control. — Thorough cultivation of the orchard and destruction of
weedy borders in May and June.

ORDER HEMIPTERA ( = FORMER SUB-ORDER HETEROPTERA)

Chief Economic Families' (after Comstock) (Fig. loi)

A. Antennae with 3-4 segments.
B. Beak 3-jointed.

2

Fig. ioi. — Fore wings of Heteroptera. i, Capsidae; 2, Pyrrhocoridas; 3,
Lygaeidae; 4, Coreidse; 5, Nabidse; 6, Acanthidas; 7, Typical wing showing parts:
m., membrane; cm., cuneus; e., embolium, co., corium; cl., clavus. (^Afler Comstock.)

1 Other Hemiptera Families are of frequent occurrence, especially in or about
water. For convenience of reference the common families (old Hepteroptera) are
synopsized as follows:

A. Shorl-horned Bugs.— Live in or near water; antennae short and concealed
beneath the head.

Families: Corisidae, Notonectidae, Nepidae, Belostomatidae, Naucoridae,
and Galgulidae.
AA. Long-horned Bugs. — Antennae at least as long as the head.

B. Semi-aquatic Bugs. — Saldidae, Veliidas, Hydrobatidaj, Limnobatidae.
BB. Land-bugs.

C. Antennas 4-jointed. Emesidae, Reduviidas, Nabidae, Phymatidae,
Aradidae, Tingitidae, Acanthiidae, Capsidae, Pyrrhocoridae,
Lygaeidae, Berytidae, Coreidae.
CC. Antennae 5-jointed. Pentatomidae, Cydnidae, Corimclsenidae,
Scutelleridae.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 59

C. Front legs with thick iemora..—Fliymalidce (Ambush-Bugs)

P- 43-
CC. Front legs normal or slightly thickened.

D. Body not flattened. — Rednviida (Assassin Bugs), p. 43.
DD. Body flattened.

E. Tarsus with 2 segments. — AradidcB (Flat Bugs).
EE. Tarsus with 3 segments, dorsum flat, beak short. —
Acanlhiidce (Bedbugs), p. 167.
EB. Beak 4-jointed.

C. Ocelli absent.

D. Membrane of front wings with about eight branching
veins; cuneus absent and with two large cells at base.—
Pyrrhocorida (Red Bugs).
DD. Membrane of front wings with no branching veins;
cuneus present and with one or two closed cells at base.
—Miridce or Capsida (Leaf Bugs), p. 163.
CC. Ocelli present.

D. Front legs fitted for grasping. — Nabidce (Damsel Bugs),

P- 43-
DD. Front legs normal.

E. Membrane of front wings with 4 or 5 simple veins
arising from its base. — Lygaida (Chinch Bugs), p.
161.
EE. Membrane of front wings with many forked veins
arising from a transverse basal vein. — Coreidce
(Squash Bugs), p. 159.
AA. Antennae with 5 segments.

B. Scutellum flat, narrowest behind; tibiae usually without spines.-^
PentatomidcR (Stink Bugs), p. 166.
BB. Scutellum convex, covering nearly the whole abdomen; tibiae strongly
spinose; prothorax rounded in front and straight behind; scutellum
margin furrowed. — Corimelanidce (Negro Bugs), p. 167.
BBB. Scutellum convex; prothorax not as above; scutellum with lateral
margin unfurrowed. — ■Scukllerida.

CoREiD^ (Squash Bugs)

Box-elder Plant Bug (Lepiocoris trivittatus) . — ^Leaves attacked turn
yellow and drop. Occurs in the West and is spreading eastward.

Adult. — A blackish bug 3^^ inch long, with three broad red lines on
the black thorax; veins of wings red, also edges of harder parts of wings;
mature in autumn. Hibernates under rubbish or in crevices.

Eggs. — ^Laid in spring and early summer on box-elder trees.

i6o

ECONOMIC ENTOMOLOGY

Nymphs. — Also show bright red markings of adult. Very young
forms are bright red; mature in less than 2 weeks.

Control. — Collect bugs in sunny days in winter from trunks of trees;

spray young forms with tobacco-
soap solution.

Squash Bug (Anasa tristis
DeG.). — (Consult Cir. 39, Div.
Ent., U. S. Dept. Agr.) Infests
pumpkins and squashes. A suck-
ing insect which should not be
confused with the cucumber or
squash beetle.

Adult. — Dirty blackish-brown
above and mottled-yellowish be-
neath; ^ inch long; wings folded
diagonally across the back; beak
4-jointed; ill-smelling (Fig. 102).
Eggs. — ^Laid in clusters on the
underside of leaves; red or bronze,
smooth and shining; slightly flat-
tened on two sides; j^^s inch long. Hatching in 8-13 days.

Nymphs. — When newly hatched they are red and green but later
they become black like the adults but without wings and with propor-

PiG. 102. — Squash bug {Anasa tris-
tis): a, mature female; b, side view of
head showing beak; c, abdominal seg-
ment of male; d, same of female. (After
Chittenden.)

Pig. i03.^Nymphs of squash bug, showing five stages. (After Chittenden, U. S.

Bur. Ent.)

tionately longer legs and antennae, later developing wing pads and
becoming more and more like the adult. Five moults occur (Fig. 103).

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS l6l

Life-history. — It hibernates as an adult under rubbish, in out-
buildings, etc. In spring the adult injures the young squash plants by
sap punctures, and at that time lays eggs; nymphs reach maturity in
July-August. Two broods in a season in the South.

Control. — Spray with kerosene emulsion; trap the adults under
bits of board; destroy the egg-masses; destroy the vines in fall; plant
early squash plants among the cucumbers and melons as traps.

Lyg^id^ (Chinch Bugs, etc.)

Chinch Bug {Blissus leucopterus Say). — (Consult Bull. 95, 111. Agr.
Exp. Stn.; Bulls. 15, 69; Circ. 113; Farmers' Bull. 132, Div. Ent.,
U. S. Dept. Agr.) A serious native Ameri-
can pest, especially in the Central States to
cereals and corn crops and to timothy
meadows; widely distributed in the Eastern
half of the Continent from the West Indies
to Canada.

Adult. — A black bug, 3^^ inch long; wings
white and marked by a small black triangle
on their outer margins; bases of the antennae
and the legs are red. Short winged forms
in the East and along the sea coast and
Great Lakes. April-May, and August (Figs.
104 and 105).

Eggs. — Cylindrical, %oo inch long;squarer
at one end; whitish at first, becoming amber-ed.
in May, but in 10 days in August.

Nymphs. — Four moults, the successive instars showing changes in
size and markings, the first three often called the red stages. In the
first stage it is pale red throughout with a yellow band across the base of
abdomen; in the second stage the head and prothorax become darker,
the abdomen vermilion with pale yellow band; in the third stage the
color is decidedly darker throughout, and in the fourth the red has
disappeared, general color varying from black in front to dusky grey
behind (Fig. 106).

Life-history. — The bugs hibernate under rubbish, in thickets and in
clumps of grass. In April and May females lay their eggs on the roots

Fig. 104. — Chinch bug:
adult. {From Webster.)

Hatch in 2-3 weeks

l62

ECONOMIC ENTOMOLOGY

or the bases of the stems of wheat and grasses. Eggs hatch in 2 or 3
weeks or less. The nymphs reach maturity in 6 or 7 weeks, when a
migration occurs on foot to other plants. Eggs are laid on the stems
and leaves of corn and the nymphs attain maturity in autumn. There
are, therefore, two broods in a year.

Pig. 10^.

-Chinch bug: adults of short-winged form.
Webster.)

Much enlarged. (After

Control. — Clean up rubbish and burn the dried grasses in which the
pest winters in late fall or early spring; place barriers of dust or oil or
tar lines; plow furrow about fields to be protected; the use of muscardine
fungus.

Fig. 106. — The chinch bug: a, h, eggs; c, newly hatched larva, or nymph;
d, its tarsus; e, larva after first molt; /, same, after second molt; g, last-stage larva;
the natural sizes indicated at sides; h, enlarged leg of perfect bug; j, tarsus of same,
still more enlarged; i, proboscis, or beak, enlarged. {From Riley.)

Parasites and Enemies. — Triphleps insidiosus Say, Milyas cinctus
Fab., Agonoderus pallipes Fab., coccinellids, Reduviolus ferus, Pagasa
fusca, Blechrus, Chrysopa, quail, frog, Sporotrichum globuliferum Speg.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 63

MiRiD^ = Capsid^ (Leaf Bugs)

Four-lined Leaf Bug {Pcecilocapsus lineatus Fab.).— (Consult Bull.
58, Cornell Agr. Exp. St.) This bug is one of the most common in-
sects found during summer on field and garden vegetation. It is oc-
casionally destructive in flower gardens,

Adidt. — A greenish-yellow bug with two black spots on the thorax
and four black stripes down the back; ^f q inch long; abundant in June
and July.

Eggs. — White, laid on terminal twigs of currant and other bushes
in the fall; hatch in the spring.

Nymphs. — Red when young, but blacker when older, mature in
about 20 days. They injure the tips of shoots and cause the leaves
to curl up and become brown
spotted. Currants, gooseberries,
mint and sage are especially liable
to injury.

Control. — Spray with nicotine
sulphate or other tobacco extracts,
or kerosene emulsion.

Tarnished Plant Bug {Lygus

pratensis L.). — (Consult Bulls. 346 Pig. 107. — Tarnished plant bug (Lygus

and 391, Agr. Exp. Sta., Cornell.) Pr<^^'^^i^^- i^fl^'^ Chittenden.)
A very common insect, feeding on a wide range of plants. It causes
the well-known injury to the buds of aster, dahlia and chrysanthe-
mum, and to the buds and blossoms of orchard trees (Fig. 107),

Adult. — Brownish, mottled with yellow and reddish. Head yel-
lowish-brown, usually with three lines; pro thorax bronzy brown,
usually with four blackish spots in a row; scutellum brownish, usually
with a Y-shaped spot. Wings bronzy brown mottled with yellowish-
brown and reddish. Antennae dark brown; legs brown, tibiae banded
near base and tarsi dusky. Under surface dark at centre with a lighter
lateral stripe and a marginal brown band with yellow spots. Length
\'i to yi inch. Hibernates.

Eggs. — One-twenty-lifth inch long, flask-shaped, and obliquely
truncate; deposited in stems, etc.; duration 10 days.

Nymphs. — -Five stages; active; feeding on juices of plants.

Life-history. — Cycle completed in 25 to 30 days in late summer

164 ECONOMIC ENTOMOLOGY

with probably four or five generations each year. Adults winter in
sheltered situations; eggs laid in early spring and first nymphs appear
in May. Broods not well distinguished, and insects to be seen from
spring until fall.

Control. — No effective remedy; spraying with nicotine sulphate,
kerosene-soap emulsions and fish-oil soap is fairly satisfactory if ap-
plied in early morning.

False Tarnished Plant Bug {Lygus communis Knight). — (Consult
Can. Ent. 48, 10 and Bull. 8, Nova Scotia.) A serious pest in pear
orchards in New York State, causing knotty deformed and gritty fruit.
Plum and quince are also injured. The Var. nova scotiensis injures
apple.

Adult. — Pale green to light brown; 3^^ inch long; two black rays on
disk of pronotum; membrane of upper wing with three brown spots
near tip of areole; legs and antennae long. Most commonly breeds on
Cornus spp.

Eggs. — Smooth and cylindrical, elongated, 0.8 mm. long; yellowish-
white, translucent. Inserted in the bark of small branches July- Aug. ;
hibernate, hatching during blossoming time.

Nymphs.— 'PsAe. yellow at first, becoming greenish; feeding on the
leaves; five stages, maturing about middle to end of June. They
puncture the young fruits, often several punctures on one fruit, causing
the fruit to fall or depressions and deformities in apples and grittiness
in pears. Leaves, stems and blossoms are freely attacked. Dura-
tion about 32 days. Carrier of European Canker and Fire Blight
(Brittain).

Control. — -I. Spraying with Black Leaf 40 (i part to 1000 water)
just after the petals fall.

2. Banding the trunks to prevent the bugs from crawling up.

3. Cultivation of soil up to July to keep down all plant growths.
The Var. nova scotiensis (Green Apple Bug) occurs abundantly

as an apple pest in Nova Scotia. It is more slender and much paler
than the typical communis.

Lygus invitus Say, according to Knight, breeds only on elm, and is
not responsible for injuries to pear and apple.

A very common capsid of meadows is Miris dolobratus L., a form
long and narrow, ^^ inch long; greenish, yellow with black markings;
two black stripes extending from the eyes over the thorax.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 165

Clouded Apple Capsid (Neurocolpus nuhilus Say). — A widely dis-
tributed capsid, injuring apple trees and fruit in Ontario.

Adult. — One-fourth inch long, larger and narrower thanLygw^ pra-
tensis. Color variable, but dorsally mostly cinnamon brown to red-
dish-black; has a dull felty appearance; ventrally light green. Basal
joint of antennae stout, dark, and with clavate dark brown hair; second
segment slender, elongate; legs slender with reddish bands.

Eggs. — Curved, nearly colorless, with a glistening white cap. In-
serted into tissues of new growth; egg-laying period July i5th-Sept.
ist; eggs usually laid singly behind buds. Hibernate. Hatch about
first week in June.

Nymph. — ^This stage lasts from 3 to 4 weeks. At first nearly color-
less, but later is green with dull reddish marks on back and sides.

Control. — -Clean cultivation, until end of June; spray the leaves
thoroughly with soap and Black Leaf 40 soon after the nymphs hatch.

Apple Red Bugs {Heterocordylus malinus Renter and Lygidea
mendax Renter). — (Consult Cornell Bull. 291.) These bugs cause
spotting of the leaves, and they puncture the fruit in June, causing
deformation.

Adults. — -One-fourth inch long; Heterocordylus varies from red to
black; wings red, black along inner edge and with an ovate black spot
near outer margin; scutellum, legs and antennae black, dorsum covered
with white, scale-like hairs; Lygidea is lighter colored and without hairs
on back; head and pro thorax orange-red, scutellum orange-red in front
and blackish posteriorly; wings with a band of orange-red along outer
edges, legs darker yellow.

Eggs. — Dull whitish, curved and slightly compressed, inserted into
the bark of smaller branches; hatch soon after opening of leaves of
fruit-buds.

Nymphs. — At first red; five stages; Heterocordylus has dusky mark-
ings on thorax and no fine short hairs on thorax.

Control. — -Applications of Black Leaf 40 (i pt. to 100 gal.) just
before blossoms open, and just after falling of the petals.

Hop Red Bug (Faralacoris hawleyi Knight). — This capsid is a
pest of hops in New York. It stunts and deforms the vines and per-
forates the leaves.

Adult. — One-fourth inch long, black with hemelytra hyaline or pale
yellowish, and cuncus reddish. July.

1 66 ECONOMIC ENTOMOLOGY

Eggs- — One-fifteenth inch long, dirty white, curved and with two
prominent white incurving hooks at micropylar end; smooth and glossy.
Inserted in the bark or wood of hop poles, Aug.-Sept. Duration 9-
93-^ months. Hatch throughout June.

Nymphs. — Five stages; duration about 30 days. Active.

Enemies. — Apeteticus maculiventris , a Pentatomid; Reduviolus sub-
coleoptratus, a nabid; and a species of Tromhidnim.

Pentatomid^ (Stink Bugs)

Harlequin Cabbage Bug (Murgantia histrionica Hahn). — A native
of Mexico and Central America. Injurious in the Southern states
but its ravages do not extend much farther north than New
Jersey and Long Island. Also known as "calico bug" "fire bug,"
and "terrapin bug." Attacks cabbage, radish and turnip.

Adult. — A moderate sized red and black plant bug, the markings
running more or less transversely and alternating. In South active
throughout the year; in North hibernates as adult.

Eggs- — ^Resemble "miniature white barrels bound with black hoops
and'with black spots set in for bung-holes." Usually laid in two rows,
fastened by one end to under surface of leaf. Hatch in 2-1 1 days.

Nymphs. — Like adults in markings; antennae with 4 joints; 5
instars, first instar glossy yellow; duration 2-10 weeks but shorter in
the South. Probably 4 or 5 generations in the South and 2 or 3 in
the North.

Control. — Trap-crop of kale, rape, mustard, radish or turnip;
clean farm practice; bounties for collections.

Green Soldier Bug (Nezara hilaris Say). — (Consult Ohio Bull.
310.) In N. E. parts of U. S. and Canada; a general feeder, and a
serious pest of the peach industry in Ohio.

Adult. — Oblong-oval; bright green, finely punctate; edges of head,
thorax and abdomen white-yellowish or rufous; % inch long. Hiber-
nates.

Eggs. — ^Light yellow; oval; circular cap with a row of short spine-
like processes. Laid in clusters on leaves or fruits in June- July. Hatch
in 7 to 8 days.

Nymph. — Five instars; mature in 50-75 days. Injures by punc-
turing the fruit.

Parasites. — A Proctotrypid — Trissolous euschisti Ash.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 67

In addition to the foregoing forms, among the more common
northern plant-sucking species of this family are Nezara pennsylvanica
a large green, flattened bug,^^ inch long; Cos mo pepla carnifex, shining
black and spotted with red and orange, }i inch long; Leioderma ligata,
a large broad form with a red margin and a red spot on the middle of
its back.

Among the blood-sucking species are Podisus spinosus, recognized
by the conspicuous spine on each side of prothorax, and Brachymena
spp. mostly large grey tree bugs; Perillus circumcinctus which attacks
the Colorado potato beetle.

CoRiMEL^.NiD^ (Negro Bugs)

Negro Bug (Corimelcena pulicaria Germer). — Feeds on strawberries,
blackberries, raspberries and celery, imparting an unpleasant odor.

Adult.-— K small shiny black bug }4, inch long, with a white stripe
on each side of body.

Eggs. — Orange-yellow, oval; laid singly on the leaves; hatch in
about 16 days.

Nymphs. — Feeding on leaves and fruit.

AcANTHiiD^ (Bed Bugs)

Bed Bug (Cimex ledularius L.). — Adult. Reddish-brown, ^i
inch or less in length; never fully winged but with wing pads;
flattened; hiding in day-time in cracks but active at night; "buggy"
odor.

Eggs. — ^White, oval, 3'^o inch long; laid in cracks and crevices;
each female lays about 200 eggs, 50 at a time.

Nymphs. — White at first but red after feeding; resemble adults
but body more slender and head larger; 11 weeks to mature; one
generation in a season.

Cow/ro?.— Fumigate with sulphur or carbon bisulphide; wash
floors thoroughly with soapsuds and spray with benzine.

ORDER SIPHUNCULATA (SUCKING LICE)
Chief Families

A. Eyes large, convex, distinctly pigmented; beak short. —
PediculidcB.

AA. Eyes very indistinct or wanting; beak long. — HcEmatopinidcs.

1 68

ECONOMIC ENTOMOLOGY

^ Pediculid^

(Consult Bull, s, Div. Ent., U. S. Dept. Agr.; Bull. 48, Minn. Agr. Exp. St.)

Most domestic animals at some time or other are liable to become
infested with sucking lice which cause considerable irritation. The
eggs or "nits" are attached to the hairs, and the lice by means of a
beak suck the blood of their victims.

Treatment consists in the application of tobacco water or Black

Leaf 40 ( I part to 1000 water), dilute carbolic acid, kerosene emulsion,

sulphur and mercuric ointment, or an infusion of 4

oz. stavesacre and i oz. hellebore, or creolin solution.

Two genera are of importance economically —

y^c^^'^HiiHt^ P'^diculiis occurring on man, and Hcematopinus on

V _r;:^^w»^ ^ domestic animals.

Head-louse of Man {Pediculus capitis De Geer).
— Whitish with faint dark markings on sides. Eggs
(50) glued to hairs, whitish, hatch in 6 days and
young become mature in about 3 weeks (Fig. 108).
Body-louse of Man {Pediculus vestimenti Leach) .
— Similar in shape to preceding, but larger and at
maturity with upper surface transversely banded
with black. Eggs laid in the folds in clothing.
Bacot {Parasitology, 191 7) states that P. capitis and
P. vestimenti may cross-pair with fertile offspring.
He found that the average number of eggs per day
was 3.7 for capitis and 6.4 for vestimenti. The egg period for the
latter was estimated at 12 days, and 12 days more for the maturity
of the female. "Allowing an average of 8 eggs per day, spread
over a fertile period of 40 days we find that during her life a single
female may have 4160 offspring." A carrier of typhus fever. A
common pest of army camps.

Control Measures. — Change clothing as often as possible; wash
infested clothing with a cresol soap made as follows: water 10 gal.,

Fig. 108.—
Head louse {Pedi-
culus capitis). En.'
larged.

Jeyes' Fluid

H oz.

soft soap 1^2 ''^-5 bathe body using cresol soap;

place N.C.I, powder in shirt and trousers (naphthaline 96 per cent.,
creosote 2 per cent., iodoform 2 per cent.).

Crab-louse of Man {Pediculus pubis = Plithirius inguinalis Leach) .
— Body as wide as long, with strong legs. Eggs glued to hairs. Mouth-

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 69

parts form a fleshy, extensible, unjointed beak. Tarsi with a strong
curved claw.

Control. — Cleanliness, sulphur and mercurial ointments.

H^MATOPINID^

Hog-louse {HcBmatopimis urius Nitzsch). — One-fourth inch long;
broad abdomen, long head; grey with sides black.

Horse-louse {Hamatopinus asinilAnrv.) .■ — One-sixth inch long, half
as wide, long and slender head with parallel sides.

Short-nosed Cattle-louse {Hcematopinus eurysternus Nitzsch). —
One-sixth inch long, half as wide; head rounded in front, as wide as long.
Infests the neck and shoulders chiefly. Eggs white, hatching in 7-8
days; life-cycle 22-24 days. Each female lays from 35-50 eggs.

Long-nosed Cattle-louse {Hcematopinus vituli Linn.). — One-eighth
inch long, one-third as wide; long slender head. Life-cycle from 25-
27 days.

Dog-louse (HcBmaiopinus piliferus Burm.). — One- tenth inch long,
abdomen wide, yellowish.

VI. LEPEDOPTERA (BUTTERFLIES AND MOTHS) 1

Common Families (Figs. 109-121)

A. Antenna; club-shaped at apex; wings at rest held erect; day-fliers. — The
Butterflies (Rhopalocera).
B. Butterflies with cubitus apparently 4-branched. — Papilionidce (Swal-
low-tails), p. 174.
BB. Butterflies with cubitus apparently 3-branched.

C. Fore-legs normal. — Picrida (Pierids), p. 175.
CC. Fore-legs reduced in size. — Lycanidce (Gossamer-wings).
CCC. Fore-legs aborted, mere tippets. — Nymphalida- (Four-footed
Butterflies), p. 176.
A A. Antennae clubbed but terminated by a hook; wings at rest usually held
erect. — Hesperida (Skippers).
AAA. Antennae not clubbed at apex; wings at rest held flat or folded like a roof
over the body. — The Moths (Heterocera).
B. Hind wings with one or two anal veins. — {Macrolepldoptera in part).
C. Frenulum present.

D. Subcosta and radius of hind wings connected by a strong
oblique vein. — Sphiiigidcc (Hawk Moths), p. 177.

1 Handlirsch groups the orders Mecoptera (Panorpatse), Trichoptera and Lepidoptera under
the Sub-class Panorpoidta. .

2The Danaidce family is now separated from the Nymphalidae on the basis of the bare
antennae and forked base of subcostal vein.

1 7©

ECONOMIC ENTOMOLOGY

DD. Subcosta and radius of hind wings not connected by a cross
vein.
E. Cubitus of fore wings apparently 3-branched.

F. Basal part of subcosta of hind wings joined to

radius for a distance then bending sharply toward

costal margin. — Geometrina (Geometrids), p. 204.

FF. Basal part of subcosta of hind wings not as in F. —

Notodontidce (Prominents), p. 198.

Fig. 109. — Venation of a papilionid
{Papilio) . {After Comslock.)

Fig. no. — Venation of a pierid
(Pieris). (After Comstock.)

EE. Cubitus of fore wings apparently 4-branched.

F. Subcosta of hind wings either separate from

or joined for a short distance to radius.

G. Ocelli absent; antennae pectinate; cubitus

of hind wings apparently 4-branched. —

Liparidce = Lymantriida (Tussock

Moths), p. 200.

GG. Ocelli present; antennae mostly simple;

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 171

5j__«2^=_B3

"aJA

Fig. III. — Venation of a danaid
{Danais). {After Comslock.)

2d A

Fig. 112. — Venation of a saturniid
{Anisota). {After Comslock.)

Rz R3

Fig. 113. — Venation of a
geometrid (Dyspteris). (After
Comslock.)

Fig. 114. — Venation of an
arctiid {H alisidota) . (After Corn-
stock.)

172

ECONOMIC ENTOMOLOGY

,-Ri,.J'3.

A A ^ A

Fig. 115. — Venation of a notodontid Fig. 116. — Venation of a noctuid

{Noiodonta). {After Comstock.)

{A gratis). {After Comstock.)

id A

Fig. 117. — Venation of a lasiocampid
{Malacosoma). {After Comstock.)

A A

Fig. 118. — Venation of a pyralid
{Pyralis). {After Comstock.)

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 73

cubitus of hind wings apparently 3-
branched. — NoduidcB (Owlet Moths), p. 184.

3dA l^^

Fig. 119. — Venation of a tortricid
(Cacoecia). {After Comslock.)

Fig. 120. — Venation of Thyridopleryx.
{After Comstock.)

Fig. 121. — Venation of a cossid {Prionoxystus). {After Comstock.)

FF. Subcosta of hind wings united with radius for a
considerable distance; cubitus of hind wings
apparently 4-branched. — ArctiidcB (Tiger Moths),
p. 18 r.

174 ECONOMIC ENTOMOLOGY

CC. Frenulum absent.

D. Cubitus of both wings apparently 4-branched.

Hind wings with humeral veins. — LasiocampidcB (Tent-
caterpillar Moths), p. 203.
DD. Cubitus of both wings apparently 3-b ranched; tongue
absent; tibia without spurs. — Saturniina (Silkworm Moths),
p. 179.
BB. Hind wings with usually three complete anal veins. (2 to 4 anal veins
in hind wings of ^geriidae).
C. Wings transparent; free from scales; fore wings narrow. —
MgeriidcB (Clear-winged Moths), p. 216.
CC. Small moths; wings covered with scales. — (Microlepidoptera).
D. Subcosta and radius of hind wings fused or approximate.
— Pyraliditia (Pyralids), p. 207.
DD. Subcosta and radius of hind wings far apart.

E. Second anal vein of hind wings forked at base. — ■
Tortricina (Tortricids), p. 218.
EE. Second anal vein of hind wings not forked at base. —
Tineina (Tineids), p. 236.
CCC. Large or medium-sized moths; wings usually covered with
scales. — {Macrolepidoptera in part).
D. Anal veins of fore wings partially fused; hind wings some-
times with two anal veins. — Psychida (Bag-worms), p. 207.
DD. Anal veins of fore wings not fused. — Cossida (Carpenter
Moths), p. 237.

Note. — -The Geometrina includes the following families: Ennomidse, Geometridse,
Hydriomenidae, Sterrhidae and Monocteniidse.

The Pyralidina includes the Pyraustidae, Pyralididae, Galeriidae, Crambidae,
Phycitidae, Pterophoridae and Orneodidse.

The Tortricina includes the Eucosmidas, Conchylidas and Tortricidae.

The Tineina includes Tineidae, Yponomentidae, Plutellidae, Gelechiidae, Hap-
loptiliidae, Lyonetiidae, Nepticulidae, Tischeriidae, Gracilariidae. (Consult Com-
stock's Manual and Barnes and McDunnough's Checklist of Lepidoptera.)

PAPILIONID^

These butterflies are called "Swallow'- tails" and are readily recog-
nized. The more common forms are the Tiger Swallow-tail (Fapilio
turnus, two forms), the Zebra Swallow-tail {Papilio ajax, three forms),
the Green-clouded Swallow-tail {Fapilio troilus) and the Black Swallow-
tail {Papilio polyxenes) which feeds on celery and other members of the
carrot family.

Black Swallow-tail {Papilio polyxenes Fab.).

Adult. — Wings black with two transverse rows of yellow spots on the
hind wings; between the rows of yellow spots are several flashes of blue.
Two broods, May and July. Wing expanse 3-4 inches.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 75

Eggs. — Nearly spherical; honey-yellow changing in parts to reddish-
brown; laid singly on leaves of food-plant; hatch in 5 to 9 days.

Larva. — The Celery Caterpillar; mature form 2 inches long; green,
each segment with a black band and spotted with yellow. Scent-
horns orange.

Chrysalis. — Dull grey, mottled with dull brown, roughened with
larger projections pointing forward; swung in a loop of silk; summer
chrysalis lasts from 9 to 18 days; hibernates.

Control. — Hand-picking, or the application of arsenicals for large
infested areas.

PIERIDiE

The more common butterflies of this family are the Cabbage
Butterfly (Pieris rapce), the Grey- veined White {P. napi), the Check-
ered White (P. protodice) the Clouded Sulphur {Eurymus philodice)
and the Alfalfa Caterpillar {Eurymus eurytheme).

Cabbage Butterfly {Pieris rapcelAnn.). — Introduced from Europe via
Quebec about i860. Occurs throughout United States and Canada.

The caterpillars first injure young plants, riddling the outer
leaves, later they attack the tender inner leaves where they are hard to
poison, and which they render unsightly by reason of the abundant dark
green excrement. Sometimes they eat into the centre of the head of
cabbage where it is impossible to deal with them.

Adult. — Wing expanse 2 inches, dull white above; fore wings with
black tips and two spots in the female and one spot in the male. Two
full broods and a partial third in the North, and more in the South.
Life-cycle 3 to 6 weeks.

Eggs. — Oval, yellow, ribbed, lengthwise and crosswise; laid singly
on end on the leaves; hatch in 4 to 8 days.

Larva. — The Green Cabbage worm; I'jyi inches long, velvety green
with a narrow greenish-yellow band on back and on each side. A row
of yellow spots. Matures in 10 to 14 days; feeds also on mustard and
other crucifers.

Chrysalis. — Three-fourth inch long, hght brown; attached and
swung by a girdle of silk. Winters in this condition. Duration in
summer 7 to 12 days.

Enemies. — Apanteles glomeratus, Pteromalus puparum, paper wasps,
ambush bug.

176 ECONOMIC ENTOMOLOGY

Control. — Spray every week with arsenical solution; i lb. Paris
Green, 4 lb. whale-oil soap, 40 gal. water before heads form and with
hellebore or pyrethrum after; spray with salt-tobacco solution_(i lb.,
I lb., 5 gal. water).

Pieris napi Linn, is a native species, but not so abundant as P.
rapCB. Wings nearly all white.

Alfalfa Caterpillar {Eurymus eurytheme Boisd.). — (Consult Bull.
124, U. S. Dept. Agr.) Common, and a serious pest of alfalfa in the
West.

Adult. — Yellow with the outer margins of wings black, dotted with
white in the female. A black dot in the middle of the fore wings and a
pale yellow spot in the middle of the hind wings. Two or more broods,
March-April.

Eggs. — Minute, ribbed and cross-lined, spindle-shaped; laid on the
new growth.

Larva. — Dark green, with a faint white line on each side; i inch
long. Spiracles black and red. Strips the leaves leaving bare stalks.

Pupa. — Yellowish-green, ^^ inch long, suspended, head up, by two
threads to the stalks of alfalfa, weeds and grasses.

Parasites. — Tachinids — Phorocera and Forntina; also Apanteles,
Pteromalus and Tricho gramma. A bacterial disease.

Control. — -Pasture infested fields or cut when larvae appear in
numbers; irrigate after cutting; disk in the fall; co-operation.

NYMPHALIDiE

This family includes a large number of common butterflies such as
the Fritillarias or Argynnids; the Angle- wings or Vanessids, including
the beautiful Red Admiral {Vanessa atalanta); the Painted Beauty
{Vanessa virginiensis); the Cosmopolitan Butterfly {Vanessa cardui);
the Mourning Cloak {Aglais antiopa); the Comma Butterflies {Poly-
gonia Jaunus, P. comma, the "Hop Merchant," P. progne and P. inter-
rogationis); the Purple Butterflies {Basilarchia arthemis, B. astyanax,
B. archippus). Of these the larvae of the Comma and the Red Admiral
feed on the hop.

The "Hop Merchant Caterpillar" often called the "Spring Currant
Caterpillar," attacks currants, gooseberries, hop, elm, basswood, etc.
Generally two broods a year. They are brownish-yellow and marked

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 77

with black and yellow lines. On the body are numerous branched
black tipped spines. The wings of the adult butterfly are reddish
brown bordered with a darker brown. A silvery comma mark on
surface of hind wings.

The larvae of the Mourning Cloak Butterfly feed upon the leaves of
willow, poplar, elm and dogwood and are interesting objects. There
are two generations a year, the adults wintering over and appearing
in early spring. The adults of the second brood appear in July.

DANAIDiE

The monarch butterfly (Danais archippus Fab.) is a common insect
but not of economic importance. Its larva feeds on milkweed.

SPHlNGIDiE (HAWK MOTHS)

The Hawk Moths are readily recognized both in the adult and the
larval forms. The adults are strong fliers and are beautifully colored.
They usually fly about dusk. The larvae are large and often ornamented
with stripes, and usually have a horn near the hind end of the body.
They feed on a great variety of foliage. Ordinarily they are kept under
control by parasites and birds. When occasioning damage they are
readily controlled by spraying with arsenicals and by hand-picking.

Tomato Sphinx (Protoparce quinqiie-maculata Haw.). Adult. — Ex-
pands to 4 to 5 inches; wings ashy-grey with black markings; hind
wings crossed by four blackish lines; abdomen with a black middle
line with five yellow spots on each side; appears in June and July.
Two breeds in the south.

Eggs. — Laid singly on under surface of leaves; hatch in 4 to 8 days.

Larva. — Three to 4 inches long; naked, dark-green with 8 V-shaped
white lines on side; a black horn on tip of abdomen; feeds on leaves of
tomato and tobacco.

Pupa. — ^Dark-brown, about^ 2 inches long, sheath of proboscis
forming a handle-like process; in the soil several inches below the
surface.

The Tobacco Sphinx {P. sexta) is very similar to the preceding,
feeding on the same plants. It is more abundant in the South. The
adult is brownish-grey instead of ashy-grey, with a distinct discal
12

178 ECONOMIC ENTOMOLOGY

spot on the fore wings, and six spots on sides of abdomen instead of five.
The larva has only seven oblique markings instead of eight V-shaped
ones.

Plum Sphinx {Sphinx driipijerarum Sm. and Abb.). Adult. — Ex-
pands 3 to 4 inches; body brown, wings purplish brown; fore wings with
a whitish stripe on costal margin, a fawn colored stripe on outer
margin and several black streaks; hind wings with two whitish wavy
and an outer fawn colored stripe. June.

Eggs. — Laid singly on the leaves of plum; smooth, oval, j^fs inch
long; pale yellowish-green. Hatch in 8 days.

Larva. — ^Three and one-half inches long, apple-green, with dark-
brown lateral stripe. On each side are seven oblique white bands.
Feeds on plum leaves.

Pupa. — Reddish-brown, 1^2 inches long, with a short tongue case;
in ground all winter.

Grapevine Sphinx {Ampeloeca myron Cram.). Adult. — Expands
2}/i inches; fore wings olive-grey with a curved oblique greenish-grey
band, a discal point and a triangular spot. Body green. Two broods
— June and August.

Eggs. — Round, \'2q inch in diameter; yellowish-green.

Larva. — A "Hog Caterpillar," green with yellow dots; oblique yel-
lowish stripes along sides; a white stripe with green margin from head
to horn and seven pink spots along the middle; 2 inches long. Spine
near tip of abdomen. Feeds on leaves of grape and Virginia creeper.
Often infested with braconid parasites.

Pupa. — Formed in a loose cocoon of silk, spun under leaves at the
surface of the ground.

White-lined Sphinx (Celerio lineata Fab.). Adult. — Body and fore
wings olive-brown; thorax with three parallel lateral white stripes;
fore wings with a buff stripe from inner margin to apex; hind wings
black with a reddish middle band. Probably two-brooded adults
appearing in June and September.

Larva. — About 3}-^ inches long; color variable, yellowish-green with
black spots or black with yellowish spots, with horn at tip of abdomen.
Feeds on grape, apple, plum and on purslane, chickweed, etc.

Pupa. — ^Light brown pupa formed in a smooth cavity in the ground.

Other common Hawk Moths are: Abbott's Sphinx (Sphecodina
abboUi), Apple Sphinx {Sphinx gordius), Achemon Sphinx {Pholus

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 79

achemon), Pandorus Sphinx {Pholtis pandorus) on Virginia creeper,
Twin-spotted Sphinx {Smerinthus geminatus), Thysbe Clear- wing
{H(Bmorrhagia thy she) on Viburnum, snowberry and hawthorn.

SATURNKNA (GIANT SILK-WORM MOTHS)

This super-family includes the following famihes: Bomhycida,
HemileucidcB, CitheroniidcB and SaturniidcB. The larger number of
commonly occurring forms belong to the third and fourth famihes
which may be distinguished by the presence of two anal veins in the
former and only one in the latter.

CERATOCAMPID-S (CITHERONIID^)

This family contains such magnificent forms as the Regal Moth
{Cither onia regalis) and Imperial Moth {Basilona imperialis), and the
economic Oak-worm moths {Anisota) and the Green-striped Maple-worm
moth {Anisota ruhicunda) .

Green-striped Maple-worm {Anisota ruhicunda Fab.). — The cater-
pillar of this moth injures maples of all kinds, box-elder and oak.
Usually two generations in a season.

Adult. — A pale yellow moth with a deHcate shade of pink; wing
expanse of female 1^-2 inches; her body yellow and woolly and her
head small with thread-hke antennae. Male is smaller with plumose
antennas.

Eggs. — Pale green turning yellowish; 3'^5 inch in diameter. Each
female may lay 150 eggs on the under side of leaves; hatch in 8-10
days.

Larva. — A naked pale yellow green caterpillar, striped with dark
green; armed back of the head on second thoracic segment with two
long black horns, and along the sides and anal extremity with short
black spiny projections. Two inches long in a month, when full grown.
Four moults. Goes into ground to pupate.

Pupa. — Dark brown, armed with little spines on margin of ab-
dominal segments and on thorax; anal segment ends in a forked pro-
jection. Duration two weeks.

BOMBYCIDiE

Silk-worm Moth {Bombyx mori L.). — An Asiatic species, domestic-
ated for its silk for many hundreds of years in Europe and Asia. Many

l8o ECONOMIC ENTOMOLOGY

races have been developed by selection differing in the color of the
cocoons and larvae as well as the number of broods produced in a year.

The main food plants are the white mulberry and the Osage orange.
The moth is creamy white in color, and has a wing-expanse of about
i;^^ inches.

The lack of cheap labor in America has prevented the development of
the silk-worm industry.

SATURNIID^

The members of this family are often called the Giant Silk-worms
and include several conspicuous forms such as the lo Moth (Automeris
io), the Polyphemus Moth (Telea polyphemus), the Luna Moth {TropcEa
luna), the Fromethea Moth (Callosamia promethea) and the C ectopia
Moth (Samia cecropia).

A. Wings bluish-green with four eye-like spots; hind wings with long tails;
front border of fore wings purple-brown; larva pale bluish- green with a
pearl-colored head and two yellow stripes along the back; feeding on walnut,
hickory, etc. — Tropcea luna L. (Luna moth).
AA. Wings not green.

B. Wings yellowish or brownish.

C. With four oval, window-like spots, one near centre of each wing;
a dusky band edged with pink along margin of wings; larva light
green with an oblique yellow line on side of each abdominal
segment, feeding on many forest and orchard trees. — Telea
polyphemus Cram. (Polyphemus moth).
CC. With eye-like spots on hind wings only; ground color of wings of
female purplish-red; that of male bright yellow; larva yellowish-
green, edged with white on side, with many black-tippea branched
spines; feeding on cherry, apple, elm, oak, etc. — Automeris zo L.
(Io Moth).
BB. Wings brown, never yellowish.

C. With eye-like spots near apex of fore wings, and 4 crescent-
shaped discal spots, one near the centre of each wing, white
surrounded by reddish and black lines; thorax red, abdomen
red and banded with black and white lines; larva bright green
with four prominent coral-red and two yellow tubercles on
thoracic segments, and smaller yellow tubercles on abdominal
segments; feeding on fruit and shade trees. — Samia cecropia
L. (Cecropia Emperor Moth).
CC. With eye-like spots near apex of fore wings, discal spots angular;
in male color blackish and discal spots faint; larva bluish-green
with rows of black tubercles, excepting those on second and third
thoracic segments which are coral-red, and a yellow one on eighth

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS l8l

abdominal segment; cocoon in a folded leaf. Feeds on leaves of
fruit and forest trees. — Callosamia promcthea (Promethea Moth).

These handsome moths are not of much importance economically.
Their larvae are large, conspicuous and brilliantly colored, consequently
are readily destroyed by birds. Many also are killed by parasites. Some
attempts have been made to manufacture the silk of the cocoons
of some species but it has been found that the cocoon cannot be profit-
ably unwound on account of the large number of breaks in the thread.

ARCTIID^ (TIGER MOTHS)

Woolly Bears. — Several interesting and common caterpillars may
be conveniently grouped as "Woolly Bears," on account of their hairy
appearance. A few common forms are here considered.

Yellow Bear (Diacrisia virginica Fab.). — Color of caterpillar vari-
able; frequently yellow or straw color with a black interrupted line
along each side of back, and a black transverse line between each
segment; hairs long and yellow; uneven in length and not gathered
into pencils. Cocoon is light and composed of hairs in which pupa
passes the winter. Moth snowy- white; wings marked with a few
black dots; three rows of black spots on abdomen.

Hedge-hog Caterpillar {Isia isabella Sm. and A.). — An ''evenly
clipped furry caterpillar, reddish-brown in the middle and black at
either end." Passes winter as larva. Moth (Isabella Tiger Moth)
has wings and body orange-buff, hind wings tinted with rose. Body
with 3 rows of black dots.

Salt Marsh Caterpilar {Estigmene acrcea Drury).— Body and head
blackish with pale longitudinal stripes on the back; hair is dark brown;
passes winter as pupa. Abdomen of moth orange; both wings white
in female, hind wings orange in male; both marked with black dots.
Six rows of black spots on abdomen, one on back, one on venter, and
two on each side.

Fall Web Worm {Hyphantria textor Harris). — Conspicuous by their
webs or nests in autumn on orchard, shade and forest trees (Fig. 122).

Adult. — Quite variable in markings; pure white, sometimes spotted
with black; expands i3^ inches; femur of forelegs orange and legs and
feet with touches of black.

Eggs. — L2,id in a flat cluster of about 400 on under side of leaf;
golden-yellow, globular and pitted; hatch in about 10 days.

I82

ECONOMIC ENTOMOLOGY

Larva. — When young is pale yellow with two rows of black marks
along the body, head black; hairs sparse; and when full grown is
covered with long whitish hairs arising from black and yellow warts;
I inch long; spins webs and feeds within them; about five moults.

Pupa. — Cocoon of silken web interwoven with hairs; pupa dark
brown. Winter passed as pupa.

Fig. 122. — Fall web worm 'Hyphantria texlor): a and 6, caterpillars; c, pupa; d,
adult moth. {After Howard, U. S. Bur. Ent.)

Life-history. — Hibernates as a pupa under rubbish, in crevices
under walls, etc. Moths emerge in June; eggs hatch in about lo days
and caterpillars mature in August and September. Two broods in
some localities.

Parasites. — Telenomus bifidus Riley, Meleorus hyphantrice Riley,
Apanteles hyphantrics Riley, Limneria pallipes Prov., Tachina sp.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 83

Control. — Prune off and burn the webs; spray with arsenical; collect
and destroy the cocoons.

Hickory Tiger Moth {Halisidota caryce Harris). — (Consult Bull. 598,
U. S. Dep. Ag.) Adult. — A yellow and brown moth, 2 inches wing
expanse; fore wings long, narrow and pointed, ochre-yellow with five
irregular transverse incomplete rows of spots. June- July. One brood
a year. Distributed over the Northeastern States and the Eastern
provinces of Canada.

Eggs. — Blue and nearly globular a brown ring on upper surface; laid
in patches of 100 or more on under side of leaf in early summer.
Duration 15-16 days.

Larva. — One and one-half inches long; gregarious at first; feeds
on the leaves of hickory, butternut, apple and other trees; covered with
dense and spreading tufts of white hairs, has a row of 8 black tufts on
the back and two long slender black pencils on the fourth and tenth
segments; head, feet and under surface of body black ; upper surf ace of
body white with black dots. Eight to nine feeding stages, and about
a week as larva in the cocoon. Larvae feed gregariously during the
first four stages. Duration 70-90 days.

Pupa. — ^Cocoon greyish, oval, hairy, ^ inch long, found under boards
and rubbish on the ground; pupa reddish-brown, caudal end with a
transverse row of spines.

Checkered Tiger Moth {Halisidota tessellaris Sm. and A.). — ^Like
preceding species but tufts are yellow; two orange colored pencils on
second and third segments; two white pencils on sides of third and
eleventh segments.

Spotted Halisidota {H. maculata Harris) .^ — Larva with yellow tufts
in the middle and black tufts at either end, and a row of black spots
down the centre. Occurs on apple, maple, birch, alder, poplar, oak,
etc. Cocoon is yellowish, oval and hairy.

Parasites of Cocoons. — Scambus pedalis, Theronia melanocephala,
Amblyteles malacus.

AGARISTID^ (WOOD MOTHS)

Eight-spotted Forester {Alypia odomaculata Fab.). — A frequent
feeder on the leaves of wild and cultivated grapes, and Virginia creeper
in eastern U. S. and Canada, sometimes doing considerable injury.

1 84 ECONOMIC ENTOMOLOGY

Adult. — General color a deep velvety blue black. Fore wings with
two large circular pale yellow spots, and hind wings with two smaller
white spots. Wing expanse iH inches. May- July. Single brooded.

Larva. — One and two-fifth inches long; bluish-brown; head and cervi-
cal shield bright orange with black spots. Each segment crossed with
black, white and orange bands; eleventh segment with a prominent
hump; legs black; base of prolegs orange. Full grown in early August.

Pupa. — A chrysalis within a slight cocoon just below the surface of
the ground. Hibernates.

Parasites. — Winthemia 4-pustulata Fab. — A tachinid.

Control. — Spray the larvae with arsenate of lead or pyrethrum.

NOCTUID^ (OWLET OR MILLER MOTHS)

According to their manner of feeding on plants the larvae of Noctuids
may be classified roughly into: (a) Cutworms proper, feeding on roots

Fig. 123. — Mouth parts of a caterpillar, the striped cutworm (Euxoa tessellata) :
Ant., antennae; CI., clypeus; Lb., labium; Md., mandible; Mp., maxillary palpus;
Lbr., labrum; Mx., maxilla; S., spinneret.

of grasses and cutting off young plants at surface, (b) Army-worms,
eating the leaves of cereal and other crops, (c) Climbing cutworms,
feeding on buds of fruit trees, (d) Loopers and caterpillars, feeding
on leaves of turnip, cabbage, celery and other plants, {e) Ear-worms,
feeding on kernels of corn in the field. (/) Stalk-borers, feeding in
tunnels made in stems, (g) Green Fruit-worms, feeding on the surface

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 85

of apple, etc. {h) Dagger Caterpillars, feeding on the leaves of many
shrubs and trees, {i) Underwing Moths, some feeding on the leaves
of trees (Fig. 123).

(a) Cutworms Proper

(Consult Bull. 95, 111. Agric. Exp. Station, 1904; Bull. 10, Div. Ent. Can., 1912)

There are many species of cutworms that feed upon economic
plants. They are mostly "plump, soft-bodied, cylindrical caterpillars,
dirty greyish or whitish, and variously spotted and striped" (Forbes).
They are the larval stages of species of Noctuid moths, commonly
termed "millers," and are night feeders. ''They are essentially grass
and clover insects, and by far the greater part of them are bred in
pastures and meadows."

Life-history. — The majority of the species hibernate as partly
grown larvae, and enter the ground to pupate m late June and early
July. The adults — usually greyish nocturnal moths — emerge in
early August and lay their eggs in grass lands. Each moth may lay
from 200 to 500 eggs, either in masses or singly. The larvae that
hatch from these eggs feed on the roots of grasses until winter sets
in. Feeding is resumed in the spring, when most serious injury is done,
until their larvae pupate in June- July.

Control of Cutworms. — Plow grass land in midsummer or early fall
to prevent the female moths from egg-laying; late fall plowing of grass
lands will destroy many of the hibernating cutworms; allow poultry
and hogs upon cutworm land; use poison bait: bran 20 lb., molasses
I qt., paris green or white arsenic ^2 lb., water 2}^-^ gals.

Natural Enemies. — Calosoma calidum, Ammophila luctuosa, Win-
themia 4-pustulata.

The following species are most commonly met with:

Spotted Cutworm {Agrotis c-nigrum Linn.). — General color grey to
brownish; a row of triangular black spots along each side of back; a
pale line down the middle of back, a conspicuous whitish-yellowish
stigmatal band, and a pale intermediate line; head and shield yellowish-
brown; front feet pale brown and shiny, i^-^ inches long. Active in
April and May in vegetable gardens (Fig. 124).

W-marked Cutworm (Agrotis unicolor Wlk.). — General color pale
brown; four rows of dark spots and often also with lighter lines along
the back, resembling the letter W; sides of W-marks bordered with

1 86

ECONOMIC ENTOMOLOGY

pale yellow; head pale brown with a wide black dash on each side;
shield dark brown. Active in April and May in gardens and orchards
(Fig. 125).

Greasy Cutworm {Agrotis ypsilon Rott.)- — General color dark greasy
grey to black above and greenish-yellow below; a pale yellow line
down centre of back, and three others on each side; tubercles black and
shiny; head and shield dark brown; ij^^ inches long. Active in May
and early June on corn and garden vegetables (Fig. 125).

Variegated Cutworm {Lycophotia margaritosa Haw.). — One and
three-fourth inches long; color variable from grey to brown; body
mottled with dark brown; a yellowish band along each side; a series of

Fig. 124. — a. Spotted Cutworm, dorsal aspect; b. Spotted Cutworm, lateral
aspect; c, White Cutworm; d, Dingy Cutworm; e. Black Army Cutworm, dorsal
aspect; /, Black Army Cutworm, lateral aspect. {After Gibson, Bui. 10, Ent. Br. Can.)

yellow dots or spots along the middle of back; two stripes of velvety
black blotches bordered with orange and black curved dashes between
the lateral yellow band and the middle of the back; head reddish-yellow
and marked with black bands resembling slightly the letter H. Prac-
tically an omnivorous feeder, its food plants including cereal root,
forage, vegetable flowers and orchard trees. Active in May and early
June in gardens. The eggs are laid in irregular masses upon the stems
of plants; they are small, white, hemispherical and ribbed. The pupae
are reddish-brown and about % inch long.

Dark-sided Cutworm {Euxoa messoria Harris). — General color
greyish; sides darker than rest of body; a dark line down middle of

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 187

back; tubercles blackish, each with a single hair; head and shield shiny
and grey. Active in May and June on fruits and garden vegetables.
Sometimes called the "onion cutworm."

Common Striped Cutworm {Euxoa tessellata Harris). — This cutworm
is 1 3^^ inches long, grey, with a pale median dorsal line and three pale
lines on each side. It feeds on most vegetable crops. One brood a
year; passes the winter as half-grown larva, and is most destructive
in June. The moths appear in July and August.

Red-backed Cutworm {Euxoa ochrogaster Gn.). — With a broad
reddish stripe down the back; head and shield yellowish-brown, the

Fig. 125. — a. Red-backed Cutworm, dorsal aspect; b. Red-backed Cutworm,
lateral aspect; c, Greasy Cutworm, dorsal aspect; d, Greasy Cutworm, lateral aspect;
e, W-marked Cutworm, dorsal aspect; /, W-marked Cutworm, lateral aspect.
{After Gibson, Ent. Br. Can.)

former with two distinct black marks toward the centre. Along
middle of back a pale stripe, and at each side a dark stripe borders the
red of the back. Tubercles small and dark, each bearing a single
hair. Moth variable in color and markings. Ground color of wings
pale yellow to dark red; fore wings crossed by four or five irregular
lines and marked with black; body grey or dull brown; active in May,
June and July on corn (Fig. 125).

Army Cutworm {Choriza gratis auxUiaris Grote). (Consult Bull. 13,
Entom. Branch, Ottawa.) Three varieties: C. auxUiaris, C. intra-

i88

ECONOMIC ENTOMOLOGY

ferens, and C. agrestis are recognized as destructive to grain, alfalfa,
beets and flax in the West in Montana and Alberta. The larvae begin
to mature about the middle of May but pupation m earthen cells does
not occur until the middle of June. The moths fly from June 15th-
Sept. 30th and the eggs are laid from August 24th-October 15th in
the soil in weedy summer-fallows.

Porosagrotis delorata Sm. is injurious to wheat in June. In British
Columbia Eiixoa excellens Grote injures market gardens, and Neuria
procincta Grote injures farm crops (Fig. 127).

Glassy Cutworm {Sidemia devastator Brace). — Translucent whitish,
tinged with bluish-green and without spots; tubercles brown, each with
a single hair; head reddish-brown; neckshield brownish. Active in

Fig. 126.-

-a, Moth of Glassy Cutworm {Sidemia devastator); b, larva.
Gibson, Bui. lo, Enl. Br. Can.)

{After

May and early June on hay and garden vegetables. Difficult to
kill by poison bait on account of its underground feeding habit
(Fig. 126).

Yellow-headed Cutworm {Septis arctica Bdv.). — Pale smoky grey,
with head and neck shield tawny-yellow; without spots, ij^^ inches long.
Active in July on cereal crops and vegetables. (Fig. 127).

Bronze Cutworm {Nephelodes emmedonia Gn.). — ^Large, i^ inches
long, with alternate stripes of olive-bronze and yellowish, a pale stripe
along the middle of the back, and two others on each side. Active
in grass lands in April and May.

Zebra Caterpillar {Cer arnica picta Harris). — "Velvety black on the'
back; beautifully ornamented with two golden-yellow stripes on each,
side of the body, which are connected by narrow lines of the same color;'

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 89

the head and feet reddish-brown" (Fletcher). Two broods, on cab-
bages and turnips (Fig. 128).

Fig. 127. — a, Moth of Yellow-headed Cutworm {Seplis arctica); b, moth of Clover
Cutworm {Scologramma Irifolii); c, moth of Pale Western Cutworm. {Porosagrolis
orlhogonia); d, moth of Dingy Cutworm {Felia ducens). {After Gibson, Bui. 10, Ent.
Br. Can.)

Fig. 128. — The zebra caterpillar and moth (Ceramica picla).

Clover Cutworm {Scotogramnia trifolii Esp.). — Color varying from
green to dark; a pale yellowish line along middle of back, a pinkish
band bordered with white or pale yellow along each side, and between

19° ECONOMIC ENTOMOLOGY

these a broken yellow stripe; head pale yellow or green with white
mottlings; under side greenish grey with spots and streaks. Damages
peas, clover, root crops, lettuce, etc. August (Fig. 125).

(b) Army "Worms

The Army Worm [Cirphis unipuncta Haw.). — (Consult Farmers'
Bull. 731, U. S. Dep. Agr.; Bull. 9, Ent. Br., Dep. Agric, Can.)
Army worms appear to be more abundant in a wet spring or summer
following a dry season. Injurious in 1895-1896 and in 1914. Prob-
ably a native of North America (Fig. 129).

Adult. — A dingy yellowish-brown moth with a white spot on the
centre of each front wing; wing expanse i3-^ inches, a row of small
black spots near outer margins of wings with dark streaks.

^S,gs- — Minute white eggs laid in bead-like strings on grass leaves
in the folded blades or under the leaf-sheaths. Hatch in 8-10 days.

Larva. — A dark-colored cutworm, i^^ inches long; body striped with
black and yellow lines; a narrow white stripe or line along middle of
greenish-black back; lower stripe dark greenish-yellow; next, just above
the spiracles, black; the lowest, just below the spiracles, light greenish-
yellow, edged with white. Head greenish-brown with coarse black
mottlings and with two curved blackish-brown bars; under surface
greenish mottled with brown; looping gait until after second moult;
duration 20-30 days. Parasitized by Winthemia 4-pustulata, Apan-
teles militaris, Ichneumon canadensis, I. lactus, I. jucundus and others;
by a bacterial disease; and preyed upon by Calosoma.

Pupa. — A brown chrysalis in the ground; duration 12-15 days.

Life-history. — There are two broods of the Army Worm moth each
season. The insects usually pass the winter as half grown caterpillars.
In the spring these mature and change to pups, the moths appearing
early in June. The May brood of caterpillars seldom does much harm.
The female moths lay their eggs (about 700) on grass leaves from
which caterpillars hatch in about 10 days. The caterpillars of this
brood do most injury. The worms usually feed at night, consequently
whole fields may be ruined before they are discovered. This July
brood of caterpillars reaches maturity in about 25 days, and changes
to pupag in the ground, the moths appearing again in about 2 weeks.
These lay eggs for a brood of worms which appear in September, but
are seldom injurious.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 191

Fig. 129. — Stages and work of the true army worm {Cirphis unipuncta) and
some of its insect enemies: a, parent or moth; b, full-grown larva; c, eggs; d, pupa
in soil; e, parasitic fly, Winlhemia quadripuslulala, laying its eggs on an army worm;
/, a ground beetle, Calosoma calidtim, preying upon an army worm, and, at right,
Calosoma larva emerging from burrow; g, a digger wasp, Sphex sp., carrying an army
worm to its burrow; h, Enicospilus purgatus, a wasplike parasite of the army worm,
natural size. (Z7. 5. Bur. Enl.)

192 ECONOMIC ENTOMOLOGY

Control. — Plow the fields in late fall; plow three or four furrows
in front of the advancing army and kill the woims that fall into the
furrows; poison a narrow strip on the threatened side of field with
Paris green or the poisoned bran mash.

Black Army Cutworm (Agrotis fennica Tausch). — General color
brown; a series of velvety black marks along middle of back; a white
line along each side, and a spiracular white band, reddish-brown
in the centre; head yellowish-red; shield black; feet pale brown.
May and early June. Attacks peas, clover, trees and some garden
vegetables (Fig. 125).

Fall Army Worm {Laphygma Jrugiperda S. and A.). — (Consult
Farmers' Bull. 752, U. S. Dept. Agr.) Injurious mainly in the
South but periodically appearing in the North. Feeds on grasses and
cereal crops, cotton, alfalfa, cowpeas and other crops.

Adult. — Wing expanse 13^^ inches; front wings dark grey, mottled,
and with a light grey spot near tips; hind wings white, with a pearly
lustre, and edged with a brown line. Body ash grey.

Eggs. — ^Light grey and minutely ribbed. Laid in clusters of 50-
200 on grass blades. Hatch in 2-4 days in South, but as long as 10
days in the North.

Larva. — Newly hatched larvae with jet-black heads and white bodies.
Full grown in 2 to 3 weeks; then striped, nearly naked and about i}^
inches long. Front of head marked with an inverted Y. Assumes the
Army Worm habit when food becomes scarce.

Pupa. — Golden-reddish at first but black later, living in an under-
ground cell. Duration 10 to 14 days.

In the Gulf States there are 5 to 6 broods annually, but in the north-
ern probably not more than one.

(c) Climbing Cutworms

(See Bull. 104, Cornell Agr. Exp. Stn., 1895; Bull. 10, Ent. Br. Dept.
Agr., Can.)

Some species of cutworms are known to have a climbing habit,
ascending not only fruit trees but also currants, gooseberries, tomatoes
etc., to feed upon the leaves and fruit. Among these are:

White Cutworm {Lycophotia scandens Riley). — One and three-
fourths inches long, yellowish-grey with whitish spots; spiracles black.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 93

Spotted-legged Cutworm {Porosagrotis vetusta Walk.). — One and
one-half inches long; black spots on legs; feeding on peach buds.

Dingy Cutworm {Feltia ducens Walk.). — Common; with wide buflf-
grey dorsal stripe; head and thoracic and anal shields dark brown.
Feeds on garden crops (Fig. 124).

{d) Noctuid Loopers

Cabbage Looper {Autographa brassica Riley). — (Consult Bull. 33,
Div. Ent., U. S. Dep. Ag., 1902, pp. 60-69.) Larva feeds on cab-
bage and related plants (Fig. 130).

Fig. 130. — Cabbage looper {Autographa brassiccE). Showing a, adult; b, larva and
pupa. Natural size. {After Chittenden, U. S. Bur. Ent.)

Adult. — A brownish-grey ''miller" moth; front wings transversely
mottled with grey, white and black, and bearing a small silver-
white spot on inner half; expanding i}^ inches; borders "of wings
scalloped.

^SS- — Silvery-white or pale green, semi-globular, with radiating
vertical ribs.

Larva. — A pale green translucent looping caterpillar, obscurely
marked longitudinally; prolegs absent from 6th and 7th segments;
2 to 4 weeks.

13

194 ECONOMIC ENTOMOLOGY

Pupa. — Invested in a white gauzy silken cocoon spun on any con-
venient object; one to three weeks. Winters as a chrysahs.

Life-history. — Probably two broods a year in Canada and north-
ern States.

Celery Looper {Autographa simplex Guen.). — (Consult Bull, t^t,,
Div. Ent., U. S. Dept. Ag.) Slightly larger than the preceding
species.

Adult. — A "miller" moth with fore wings marked with grey and
seal brown, silver mark hooked; wings expanded 2 inches; borders not
scalloped.

£gg. —Milky- white, flattened, globular; upper half grooved verti-
cally.

Larva. — ^A pale yellowish-green looping caterpillar; markings
similar to those on A. brassiccB; supra-spiracular spots black.

Pupa. — Resembles that of A. brassicce.- — (Consult Bull. t,T), Div.
Ent., U. S. Dept. Ag.).

Alfalfa Looper {Autographa calif ornica Speyer). — Widely distributed
over Western North America from Alaska and the Yukon south through
B. C, Alberta, Saskatchewan, Manitoba to California, Nevada, Utah,
Wyoming, Idaho, and Montana. Larvae destructive to the leaves and
blossoms of alfalfa, clover, garden peas, cabbage, etc.

Adult. — A brownish-grey moth, 13^^ inches wing expanse; fore wings
light bluish-grey with rose and light markings — one shaped like the
letter Gamma near the middle; hind wings dull brown. An active
flier.

Eggs. — Hemispherical, rounded at base, apex with rounded depres-
sions; finely creased vertically; pale yellow. Duration 5-7 days.
Probably laid on the leaves.

Larva. — One and one-fourth inches long, dark green, cylindrical
tapering toward the head; subdorsal line fine and wavy; two other lines
in this area and a wide whitish stigmatal band. Tubercles white, setae
white. Spiracles pale, black rimmed. Thoracic feet black, shiny.
Three pairs of pro-legs on segments 9, 10, 13.

Pupa.—Dsivk brown, % inch long. The cocoon is a thinly woven
web of whitish silk spun among the leaves. Duration 10-14 days.
Hibernates as pupa and adult. Probably two broods in B. C. and
Washington.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 195

Green Clover Worm {Plathypena scabra Fab.) (Consult Farmers'
Bull. 982, U. S. Dept. Agric). A pest of alfalfa and the leguminous
crops of eastern U. S. and southern Canada.

Adult. — Variegated dark brown to black; wing expanse i}^ inches,
2-4 generations a season. Hibernates.

Eggs. — Circular, slightly flattened; green; about the size of a pin
head. Female lays between 200-600 eggs in a few days singly on
the underside of the leaf. Hatch in about four days.

Larva. — Green, with a narrow white stripe and second fainter
white line on each side; 1^4 inches long; only four pairs of pro-legs;
5 moults; restless and drops off the plant when disturbed. Mature
in about 4 weeks.

Pupa. — -Yellow-brown or black, formed in a loose oval base or
cocoon of debris webbed together; duration about 8 days. Some-
times hibernates.

Control. — Cut the crops when the caterpillars are most abundant;
adopt clean culture; use hopperdozer in bad outbreaks.

Hop Vine Looper or Snout Moth {Hypena humuli Harris) . — This
noctuid sometimes does serious injury to the leaves of hop. Two
broods a year.

Adult. — A dark brown moth, 13^2 inches wing expanse, with irregular
and variable transverse markings on fore wings; palpi long, flattened,
and projecting horizontally like a snout. July and August-September;
hibernates.

Eggs.—Fsile green; laid on the under side of the leaves.

Larva. — -A semi-looper, lacking the first pair of prolegs; green;
with two longitudinal white lines along the back, a dark green line
between and an indistinct whitish line on each side; head green spotted
with black piliferous dots. Spins a thin silken cocoon before pupating.

Pupa. — ^Formed in the ground, in crevices in the poles, and in the
leaves. Duration about 10 days.

Control. — Spray or dust vines with arsenate of lead.

(e) Com Ear Worm (Heliothis obsoleta Fab.)

Adult. — An ochre-yellow moth with blackish markings, expand-
ing about 1 3-^ inches.

Eggs. — Small yellow circular flattened disks, prettily corrugated
by ridges radiating from the centre.

196 ECONOMIC ENTOMOLOGY

Larva. — Variable in color, pale green or brownish caterpillar, ij^^
inches long, often dark striped; head amber-yellow; legs black.

Pupa. — In a small oval cell in the ground.

Life-history. — In Canada there is one brood, perhaps two in some
southern localities. The insect hibernates as a pupa. The moth
emerges the following July, when eggs are laid on the silk of the ears.
The young caterpillars feed upon the young kernels until fully de-
veloped, when they descend to the ground and transform to pupae in
small oval cells. Known in the South as the Cotton Boll Worm.

(/) Stalk Borers

Several species of Stalk Borers are injurious to various cultivated
plants, such as hop vines, columbines, corn, potatoes, tomatoes, rasp-
berries, asters, dahlias, and also to burdocks. The caterpillar lives
inside the stem and makes a burrow by devouring the interior. As
a result the plant often withers and dies. Before maturity it works
its way down to the root where it changes to a pupa. The Stalk
Borers have been placed mthegeneTa,Gortyna,Hydroeciaa.ndPapaipema.
Gortyna immanis occurs in hop vines; Papaipema piirpurifascia in
columbine; P. nitela in corn, dahlia, aster, potatoes, etc; P. cata-
phrada in burdock; Gortyna micacea in rhubarb, corn, potatoes, etc.

Garden Stalk Borer {Papaipema nitela Guen.). — This borer tunnels
the stalks of potatoes, tomatoes, and other garden crops, and many
weeds. Sometimes feeds on strawberry. One brood a year.

Adult. — A mouse-colored noctuid moth, with outer third of fore
wings paler and bordered within by a whitish cross-line. Late August.

Eggs. — Grey, circular, with radiating ridge, 3^^o iiich in diameter;
hatch in late May or early June.

Larva. — Mines in the leaf at first, then enters the stalk and tunnels
it. Full grown about August; i inch long, purplish to light brown
and marked with white stripes except on first four segments of ab-
domen; head, neck-shield and anal-shield light reddish-yellow.

Pupa. — Brown, formed in lower part of stalk. Duration about
2 weeks.

Control. — Clean cultivation; removal and burning of old stalks.

Potato Stalk Borer {Gortyna micacea Esp.) . — ^A European insect, and
a general feeder. Reported on rhubarb, corn, potatoes in N. S. and
N. B.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 197

Adult. — Ground color of fore wings light brown tinged with red,
with a transverse darker median band. Hind wings dingy grey with
a transverse light brown line. Aug.-Sept.

Eggs. — Circular, finely ribbed and sculptured; slightly pinkish;
laid on stems of couch grass.

Larva. — One and three-fifth inches long; head chestnut-brown;
tubercles pale brown with a stiff black bristle; spiracles shiny black;
body color greyish tinged with pink.

Pupa. — Brown, f'^ inch long. Duration about 3 weeks.

(g) Green Fruit Worms (Graptolitha spp.)

G. antennata Walker, G. laticinerea Grote, G. cinerosa, G. hethunei
G. and R. and other species sometimes injure leaves and fruit of apple
and forest trees in late May and early June.

Ash-Gray Pinion {Graptolitha antennata Walk.). Adult. — Dull
ashy-grey; fore wings with darker grey or greyish-brown markings.
April and September; hibernates.

Eggs. — Yellow, globular, ridged; laid singly on bark of smaller
branches in early spring.

Larva. — ^Light yellowish or apple-green naked caterpillar, 1-13^^
inches long, with a cream-colored stripe along the middle of the back,
a similar but wider stripe along each side, and mottled markings or
stripes above the lateral stripes. Head glossy green, with white
mottlings; legs whitish, prolegs greyish. May- June.

Pupa. — -Dark brown; often within a thin silken cocoon in an earthen
cell in the ground. Duration 3 months, sometimes over winter.

Control. — Spray with dilute lime-sulphur and lead arsenate before
the blossoms open.

Parasites. — Meteorus hyphantria and Mesochorus agilis.

Bethune*s Green Fruit Worm {Graptolitha hethunei G. and R.). —
This fruit worm is a pest in many parts, and has been reported as most
destructive in the Annapolis Valley, Nova Scotia. The color of the
moth is quite variable, some moths being nearly white with darker
markings, while others are much darker.

Another species of Green Fruit Worm, Orthosia hibisci Guen.,
occurs at Geneva, N. Y.

(//) Dagger Moths

The larvae of several species of Dagger Moths may be found feeding
on the leaves of shrubs and trees. The more common forms are the

198 ECONOMIC ENTOMOLOGY

American Dagger Moth, the Raspberry Dagger Moth {A. impressa Walk.),
the Smeared Dagger Moth (A. oUinita S. and A.), the Grey Dagger
Moth {A. populi Riley), and the Darkish Dagger Moth {A. morula
Grote). They may be distinguished from the arctiid woolly-bears by
the mode of distribution of the hairs. The hairs of the latter arise
from tubercles in clusters, while they are scattered over the surface
of the body in the Dagger-larvae.

American Dagger Moth (Acronycta americana Harris). Adult.
— -Fore wings light grey with faint dark lines and dagger-like
markings. Hind wings smaller, dark brown. Body similar in color
to hind wings.

Larva. — Two and one-half inches long when full grown; thickly
covered with short pale yellow hairs, with a pair of long black hair
pencils on first and third abdominal segments and a single one on the
eighth; head black; body greenish- white above with a subdorsal and
stigmatal black line; lower surface black. Common in September on
elm, maple, oak, hickory, ash, poplar, alder and other trees.

(i) Underwing Moths

The Catocalas or U'nderwings are interesting Noctuids, the adult
moths showing protective resemblance to the bark of trees. The larvae of
some of the species at least feed on the leaves of trees, C. ultronia,
C. grynea, on apple, plum, cherry; and C. relicta, C. car a, and C.
concumbens on poplar, willow and birch.

NOTODONTEDiE (PROMENENTS)

Hand-maid Moths {Datana Spp.). — Several species of Datana occur
on orchard and forest trees.

Yellow-necked Caterpillar (Datana ministra Drury). — The larvae
are gregarious, and are often injurious to the leaves of apple in late
summer.

Adult. — A russet-brown moth nearly 2 inches expanse; head and
large spot on the thorax chestnut brown; fore wings cinnamon brown
crossed by 3-5 darker brown lines; hind wings pale yellow. Early
summer, June- July. One brood a year.

Eggs. — In flat clusters of 70-100 on surface of leaf; white and
round.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 1 99

Larva. — Two inches long; head large and black; cervical shield dull
orange; back and sides striped alternately with black and yellow lines;
body thinly clothed with soft white hairs. Larvae occur in clusters and
at rest their bodies assume a characteristic bow-form. When young
they are chestnut brown. At maturity they descend to the ground
and burrow to a depth of 3 inches. Larval stage 5-6 weeks.

Ptipa. — A naked brown object in the ground nearly an inch long.

Control. — Hand-pick the clusters of caterpillars; spray the cater-
pillars with an arsenical.

Walnut Caterpillar (Datana integerrima G. and R.) is often destruc-
tive on walnut, butternut, and hickory, and also on oak, beach, apple,
and hawthorn.

Adult. — A buff-brown moth with darker bands across the fore
wings; 1^-2 inches wing expanse. July-August.

Eggs. — ^Laid in clusters of 100 or more on underside of leaves.

LarvcB. — Caterpillars feed in clusters devouring the leaves; when
nearing maturity they separate. Body black, with a loose covering
of soft whitish hairs 2 inches long; when at rest they assume a bow-form.
At moulting times they gather in large numbers on the trunks and
larger branches. When mature they descend and enter the earth.

Pupa. — A dark brown chrysalis; hibernates in this stage.

Control. — Spray caterpillars with arsenical; collect the clusters of
caterpillars.

Red-humped Apple Caterpillar (Schizura concinna Sm. and Ab.).
Adult. — Moth expanding i3^ inches; body light brown, thorax dark
brown; fore wings greyish on outer margin and dark brown on
inner, with a brown dot near middle, a spot near each angle and
several longitudinal streaks along posterior margin. Hind wings
brownish. June and July. One brood in the Narth.

Eggs. — ^ White, round, slightly flattened deposited in a cluster of
40-100 on the under side of leaf in July.

Larva. — Body striped with yellow, black and white lines; a double
row of black spines on back; head coral-red; a red hump on fourth seg-
ment. Full-grown in late summer and fall, when they spin loose silken
cocoons, mixed with rubbish, on the ground. Gregarious, attacking
apple, pear, plum, cherry, and blackberry and some forest trees.

Pupa. — Formed in fall and pass the winter and early spring in or on
the ground.

200 ECONOMIC ENTOMOLOGY

Control.— Spra^y with arsenate of lead; hand-pick or burn caterpillars
with rag torch.

LYMANTRIID^ (TUSSOCK MOTHS)

Gypsy Moth {Porthetria dispar Linn.).— A European insect intro-
duced into the U. S. (Mass.) about 1869, now found in all the New

England States. The larva feeds on a very large variety of plants

forest, orchard and shade trees, especially oak, willow and apple,
shrubs and even herbaceous plants. Conifers immune (Fig. 131).

Adult.— MsXe brownish-yellow, slender, with feathered antenna;
fore wings marked with zigzag darker lines; wing expanse i}^ inches;
an active flier. Female white with zigzag dark lines and with slender
black antennae; body so heavy as to prevent flight.

-E^g^.— Laid in July-August in irregular oval spongy masses of
400-500 in crevices and on convenient objects, and covered with tan
colored hairs; hatching about May ist following.

Larva. — A dark brown hairy caterpillar 2-3 inches long; 2 rows of
red spots and 2 rows of blue spots along the back with a dim yellowish
stripe between; body clothed with long black hairs. Full grown about
July I St.

Pupa. — Cocoon of silk loosely formed among the leaves; pupa con-
ical and dark brown; i inch long. Duration 7-17 days.

Parasites. — The following have been introduced: Anastatus bifas-
ciatus and Schedius kuvance — chalcid egg parasites; Compsilura con-
cinnata and Blepharipa scutulata on the caterpillar; Monodontomerus
(Breus, a chalcid pupa parasite; and Calosoma sycophanta.

Control— Tved^t the egg clusters with creosote; band the trees with
burlap, etc. and spray; parasites.

Brown Tail Moth (Enproctis chrysorrhcBa Linn.). — Larva destruc-
tive to orchard, shade and forest trees. Conifers immune. Probably
introduced from Holland to Mass. about 1893 (Fig. 132).

Adult. — A white moth, except that the abdomen is tinged with
brown and tipped with a tuft of brown hairs, most conspicuous in the
female. Both sexes are strong fliers and active at night in July.

E-ggs. — In brownish clusters of 150-300 on the leaves on the tips of
the branches. Usually brown hairs are mixed with the egg mass.
Eggs hatched by August 15th.

Vic. i-ji. — Different stages of the gipsy moth (Portliclriii (li..juii]. 1"^,-: mass
center of twig; female moth ovipositing just below; female moth, Japanese

iety, lower left; male moth immediately above; female moth immediately above;

le moth with wings folded in upper left; male chrysalis at right of this; female

ysalis again at right; larva at center. All slightly reduced. (After Howard and

ke.)

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 201

Pig. 132. — Different stages of the brown-tail moth. Winter nest at upper
left; male and female adults at lower right; another winter nest at upper right;
male and female chrysalides above, male at left; full-grown larva in centre, somewhat
reduced; young larvse at its left; egg-mass, the eggs hatching at lower left; female
ovipositing on leaf; egg-mass also on same leaf. {After Howard and Fiske.)

202 ECONOMIC ENTOMOLOGY

Larva. — Dark brown caterpillar i^^ inches long with a sprinkling of
orange; body covered with fine reddish-brown hairs; a row of conspicu-
ous white hairs along each side; bright red tubercles on top of sixth and
seventh abdominal segments. Full grown in June. Winter is spent as
black quarter-grown larvae in colonies or nests of leaves bound firmly
together by a silken web. Barbed hairs irritating to human skin.

Pupa. — ^Loose cocoon attached to leaf; pupa brown, about ^ inch
long. Duration about 20 days.

Parasites. — Imported forms are: Pteromalus egregius, Apanteles
ladeicolor, Meteorus versicolor, Zygohothria nidicola, Compsilura con-
cinnata, Pales favida, Monodontomerus cereus; Calosoma sycophanta.

Control. — Cut off and burn the winter nests before the caterpillars
emerge in April; poison the caterpillars with lead arsenate before the
middle of June; parasites.

White-marked Tussock Moth (Hemerocampa leucostigma Sm. and
Ab.). — A native insect whose larva is frequently injurious to fruit trees
and shade trees.

Adult. — Male winged and ashen-grey in color; fore wings crossed
by wavy bands of a darker shade, with a minute white crescent near
outer hind angle, a small black spot near tip of outer edge and an oblique
blackish stripe beyond it. Antennae broad and feather-like. Females
wingless with slender antennae, and of a light grey color. July-
August.

Eggs. — White and nearly globular; 300-500 arranged in a three or
four-layered mass and covered with a frothy substance. Hatch in
May and June.

Larva. — One and one-fourth to one and one-half inches long, bright
yellow; head and two small protuberances on hinder portion of back
bright coral red; four creamy tufts on back; two black plumes at front
and one at the rear; black and dusky yellow stripes along the back
and sides.

Pupa. — -Cocoons made of silk and hairs; pupa brownish, the male
smaller than the female; 10-15 days duration.

Life-history. — Eggs are laid in July and August and hatch in late
May and early June; caterpillars full grown in a month; pupal stage
lasts about 2 weeks, and the adults emerge in July and August to
lay their egg-masses. But one brood in Canada and Northern United
States.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 203

Enemies. — Pimpla inquisitor, Chalcis ovata, Tachina mella; certain
birds; red ants; certain dermestid beetles; certain fungi and bacteria.

Control. — See under Antique Tussock Moth.

Antique or Rusty Tussock Moth (Notolophus antiqua Linn.). —
A European species often injurious in Nova Scotia, New England,
and the West.

Adults. — Male has rust-brown wings,»with two deep brown cross
bands and a conspicuous white spot near anal angle of fore wings. Fe-
male almost wingless with blackish body covered with yellowish- white
hairs.

Eggs. — Egg-mass laid on cocoon, but with no protective covering.

Larva. — Head black; first two tussocks on back are black at first
but whitish on later moults when an additional pencil of long black
hairs appears on each side of second abdominal segment.

Pupa. — Female larger than the male.

Control of Tussock Worms. — Collect and destroy the egg-masses;
paint the egg-masses with creosote; spray in June with an arsenical;
band trees with burlap or tar to prevent females from ascending.

LASIOCAMPIDiE (TENT-CATERPILLAR MOTHS)

Orchard Tent-caterpillar {Malacosoma americana Fab.). — Period-
ically a serious defoliator of orchard and forest trees and occurring as far
west as the Rockies. '

Adult. — A brown moth expanding 13^^ inches; fore wings crossed
obliquely by two pale lines; female larger than male.

Eggs. — A glistening brown mass (200-300) encircling the twigs,
covered with a gluey froth. Each end of belt of eggs tapers; each
egg }>'25 inch long, elongate, thimble-shaped.

Larva. — -A hairy black soft velvety caterpillar, 2 inches long, with
a white stripe down the back; on each side a row of blue spots; sides
streaked with white or yellow lines; under side blackish. Caterpillars
of a colony form silken tents at angles of branches and feed away from
tents. Matures in 4-5 weeks.

Pupa. — Cocoons formed under bark, in crevices, etc., elongated-
oval; outer silk delicate and loose, inner part firm and close; a yellow
powder within. Pupal stage lasts 2-3 weeks.

Life-history. — -Winters in the egg state; eggs hatch in May when the
buds are beginning to open and the caterpillars reach maturity in June.

204 ECONOMIC ENTOMOLOGY

Adults appear and eggs are laid in July. There is but one brood each
year.

Forest Tent-caterpillar (Malacosoma disstria Hbn.) differs from the
preceding in the following particulars: egg-mass is nearly square at
the ends; caterpillars do not construct tents; line along the back
is broken with dots; transverse lines on the wings of moth are darker
than ground color.

Parasites. — Pimpla conqiiisitor, P. inquisitor, Tachina mella,
Anomolon exile. Calosoma and Podisus are predaceous enemies.

Control. — Destroy the egg-masses; spray caterpillars with arseni-
cal; burn off the tents; band trees with burlap or tar to prevent the
caterpillars from ascending.

GROUP GEOMETRINA (GEOMETERS)

Chief Families (after Comstock)

A. Media2 of the hind wings wanting, being represented merely by a fold in the
wing. — Ennomidce.
, AA. Media2 of the hind wings present.

B. Mediaa of the hind wings arising much nearer to Mediai than to
Medias.

Wings usually green. — Gcometridce.
BB. Media2 of the hind wings arising nearly midway between Mediai
and Medias or nearer to Mediaj than to Mediai. Wings rarely green.
C. Subcosta and Radius of hind wings extending distinctly separate
from each other, except that they are connected by a cross vein
near the middle of the discal cell. — Hydriomenida.
CC. Subcosta and Radius of hind wings approximated or coalesced for a
greater or less distance.

D. Subcosta and Radius of the hind wings closely approximated
but not coalesced along the second fourth (more or less) of
the discal cell.
E. Radius and Mediai of hind wings separating at or
before the apex of the discal cell. — Ennomidce.
EE. Radius and Mediai of hind wings coalesced for a
considerable distance beyond the apex of the discal
cell.— Alonocteniida;.
DD. Subcosta and Radius of the hind wings coalesced for a short
distance near the beginning of the second fourth of the
discal cell, thence rapidly diverging. — Sterrhida.
DDD. Subcosta and Radius of the hind wings coalesced to or
beyond the middle of the discal cell.
E. Fore wings with one or two accessory cells. —
Hydriomenida.
EE. Fore wings without an accessory cell. — Monodeniida.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 20$

MONOCTENIIDiE

Spring Canker Worm {Palccacrita vcrnata Peck.). — A widely distrib-
uted insect from Canada to Texas, and from Maine to Kansas
and California.

Adults. — ^Male moth with thin brownish-grey silky wings, i inch
expanse; fore wings with a row of light markings near outer margin and
three transverse dark irregular bands; female moth wingless, 3:3 inch
long, dull grey or brown with a dark brown stripe down the middle of
the back. April-May.

Eggs. — Yellowish-green, oval, 1.^5 inch long; laid in irregular masses
of about 50 under loose bark, in crevices. Hatch in a month about
the time of unfolding of the leaves.

Larva. — Slender, cylindrical, i inch long, with only two pairs of pro-
legs, with narrow longitudinal yellow-white lines, and a yellow stig-
matal stripe along each side; ventral surface white. Mature in 4 to 5
weeks, when it drops to ground by a silk thread and enters to a depth
of 2 to 5 inches.

Pupa. — Cocoon an earthen cell lined with silk; pupa remains in it
until following spring; light brown and pitted. Male pupa spined.

Parasites, Etc. — Hymenoptera, Diptera and birds.

Fall Canker Worm (Alsophila pometaria Harris). — Widely distrib-
buted^ — -Eastern Canada, New England, New York, Ohio, California.

Adults. — Male moth with darker, stronger wings than that of the
spring Canker Worm; fore wings crossed with two light bands; hind
wings darker. Female moth wingless, ashy-grey, no markings, an-
tennae long. October-November.

Eggs. — Brownish-grey, flower-pot like, outer end with a dark spot
surrounded by a dark ring; laid in clusters of 100, in rows, each egg
fastened on end and to the bark. Hatch in May, about the time of
unfolding of the leaves.

Larva. — -Resembles in a general way that of the Spring Canker
Worm, but has a broad dark stripe along the back and three pairs of
prolegs near hind end of body. When disturbed or full grown it
drops to the ground by a silken thread. It forms a cocoon in the
ground. Matures in 4 to 5 weeks.

Pupa. — Cocoon tough and contains more silk than that of Spring
Canker Worm; pupa stouter and spine of male pupa forked.

2o6 ECONOMIC ENTOMOLOGY

Control. — Spray with arsenate of lead just after the leaves unfold;
band trees with burlap in fall.

ENNOMIDiE

Pepper-and-salt Currant Moth (Amphidasis cognataria Guen.). —
Injures leaves of currant, gooseberry, plum, Spirea and maple.

Adult. — Body grey, with black dots; wing expanse 2 inches, grey
with dark brown dots and two wavy brown cross bands on the outer
third. May and August.

Eggs. — Cylindrical, with surface marked with rows of hexagonal
depressions; }/3o inch long.

Larva. — A geometrid or measuring caterpillar, 2 inches long; green
to brownish-black in color, with indistinct green or yellow lines and
spots. Full grown in July.

PupcB. — Pupae dark brown, ^ inch long, formed in the ground.
Some change to moths in August, but others do not change until
following May.

Lime Tree Winter Moth (Erannis tiUaria Harris).— Occasionally
injurious to the leaves of elm, basswood, hickory, apple, etc.

Adult. — Male, with rusty-bufif body and fore wings, and lighter
hind wings. Female wingless, light brown to grey with markings.
Oct.-Nov.

Eggs. — Cream colored, cylindrical with ends blunt-rounded.
Hibernate.

Larva. — A bright-yellow looper, with rust-colored head, and
ten crinkled black lines along the back. Full grown larva \Y4.~'^Y2 inches.
June.

Pupa. — July-Oct.

Currant Span Worm {I tamer a rihearia Fitch). Adult. — A pale
yellowish geometrid moth with brownish spots, 13^^ inches expanse;
markings on wings variable and often with one or two cross bands.
Mid-summer.

Eggs. — Laid on twigs about July; hatch the following spring when
leaves are full grown.

Larva. — A yellow striped and black spotted looper, a little more
than an inch long; full grown in 3 to 4 weeks.

Pupa. — Formed just beneath the surface of ground; duration 2 to
3 weeks. One brood each season.

Control. — Spray with arsenical or pyrethrum.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 207

Mottled Umber Moth (Erannis defoliaria Clerck). — Destructive
in plum and cherry orchards on the Pacific slope. A European
insect, resembling the basswood or lime tree span-worm {Erannis
tiliaria) .

Adult. — Appears in November; female wingless, brown, with rows
of brown spots; fore wings of male dull ochre-brown, crossed by two
dark waved bands; hind wings pale and mottled with brown dots.

Larva. — Active in June-July; a span-worm, with black stripes sepa-
rated by reddish-brown stripes; spiracles in reddish-brown blotches.

Bruce's Measuring Worm {Rachela bruceata Hulst). — Destructive
in New York in 1886 and in Alberta in 1902-3.

Adult. — Female wingless, 3^^ inch long, light brownish-grey;
male winged, expanding i}^^ inches, pale brownish. Oct.-Nov.

Eggs. — Reddish-orange, oval, finely pitted; laid singly in crevices
of bark; hatch in April.

Larva. — Three-fourths inch long, apple-green, with three narrow
yellowish-white stripes along each side of body; head and thoracic
shield black; feeds 4 or 5 weeks in April and May, especially on blossom
buds.

Pupa. — -Light brown in a slight silk-lined cocoon in the ground.
One generation in a season.

PsYCHiD^ (Bag-worm Moths)

Evergreen Bag Worm {Thyridopteryx ephemermformis Ha worth). —
Occurs on conifers, red cedar and arbor vitae.

Adult. — Female wingless, naked and grub-like; male with trans-
parent wings. September-October.

Eggs. — Deposited in a mass within a bag composed of silk mixed with
bits of leaf and twig in September-October. They winter over and
hatch in May-June.

Larva. — Feed on the leaves within bags which are gradually en-
larged as they mature.

PupcB. — Formed within the bags.

Control. — Spray foliage with arsenical solution; gather cocoons
and bags.

PYRALIDINA GROUP

Families (After Comstock)

E. Wings not fissured.

F. Hind wings without a fringe of hairs at base of Cubitus.

2o8 ECONOMIC ENTOMOLOGY

G. Fore wings with fourth and fifth branches of Radius separate, the
latter arising from the discal cell. — Pyrauslida.
GG. Fore wings with fourth and fifth branches of Radius united at base.
— PyralididcE.
FF. Hind wings with a fringe of hairs at base of Cubitus.
G. Radius of fore wings 5-branched.

H. Maxillary palpi more or less developed but not triangular
as in HH. — Galleriidce.
HH. Maxillary palpi well developed, appearing triangular; labial
palpi long, straight and projecting forward. — Crambida.
GG. Radius of fore wings 4-branched. — Phycitlda.
EE. Wings fissured.

F. Wings with less than five fissures. — PterophoridcB.
FF. Wings with five fissures. — Orneodidce.

Pyralidid^

Meal Snout Moth {Fyralis farinalis Linn.). Adult. — A pyralid
moth, I inch wing expanse. Fore wings with base and tips dark
brown, middle portion Hght brown, two wavy white Hnes crossing
wings, bordering the middle portion, hind wings grey with two wavy
whitish lines.

Eggs. — ^Laid in masses; irregular.

Larva. — ^Lives within a silken tube; dirty-grey, darker at both
ends; head brownish-red.

Pupa. — Brownish-red, in a cocoon.

Clover Hay Worm (Hypsopygia costalis Fab.). — The caterpillars
cause injury to stacked or stored clover, near the ground or floor, by
webbing it together and contaminating it with excrement.

AduU.~^ma\\; ^i inch wing expanse; wings silky, margined with
orange and fringed with golden yellow; two large golden spots at the
thirds of the fore wings, extending to hind margin as narrow lilac lines.
Two straw colored lines on hind wing. Under surface of wings pale
yellowish; head and legs straw colored; antennae and palpi pale orange.
Two broods. June-July; August.

Eggs. — ^Laid probably on growing clover heads. June and August.

Larva. — Three-fourth inch long, dull brown; head, shield and anal
plate black after last moult; segments much wrinkled and provided
with several smooth shining areas each bearing a fine white hair.
Hibernates.

Pupa. — Honey-yellow; cocoon }2 inch long, oblong-oval, white,
silky, intermingled with excrement and bits of hay.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 209

Control. — Remove old hay and if infested burn it; raise stack above
ground a few feet on old rails, etc. Salt bottom of stack.

Grape Leaf Folder (Desmia funeralis Hhn.). — Occurs on wild and
cultivated grapes, and is widely distributed over the United States
and Canada. Causes injury by skeletonizing the upper surface of
leaves, while protected under their folds.

Adult. — Wings expanded, %o inch, dark brown and bordered with
white. Fore wings with two oval white spots; hind wings of male with
one spot, of female spot divided. Body black, crossed by two white
bands in female, one in male. Antennae of male knotted near the
middle. Two broods; May and July-August.

Eggs. — Minute, elliptical; laid singly on under side of leaf. Dura-
tion 8-10 days.

Larva. — One inch long when full grown; widest in middle; yellowish-
green on sides; head and prothoracic shield light brown; sides of first
two thoracic segments with light brown spots; six instars. Duration
about 4 weeks. First brood matures in July, second in Sept.-October.

Pupa. — Formed usually on the ground among fallen leaves. Dark
brown; tapering posteriorly. Hibernates.

Parasites. — Apanteles, Meteor us, Mesochorus, Exorista, Tachino-
phyto and others.

Control. — Spray with arsenate of lead shortly after blossoms have
fallen.

Purple-backed Cabbage Worm {Evergestis rimosalis Guen.). — Injuri-
ous in the Maritime Provinces and Southern States to turnips and
cabbages.

Adult. — Small, wing-expanse % inch; fore wings pale satiny-
yellow with a heart-shaped discal spot, two transverse wavy lines
across middle of wings, a less distinct line near base and another near
tip; hind wings silvery- white with a clear black margin. June and
Oct.-Nov.

Eggs. — Bright yellow; laid in masses of 20-40 on under surface of
leaf; hatch in a week.

Larva. — Three-fourth inch long; bristly, slender, tapering to each
end; back purplish; head, anal plate and two spots on second segment
black. July and Sept. -Oct. Full grown in 2 to 3 weeks.

Pupa. — Winters as a chrysalis. Two broods in a season, the last
brood being the more injurious. Probably three broods in the South.

2IO ECONOMIC ENTOMOLOGY

Control. — Same as for imported cabbage worm (Pieris rapes), p. 176.

Sugar Beet Web Worm (Loxostege sticticalis Linn.)- — Injurious in
Manitoba, Saskatchewan and Alberta to alfalfa, turnips, rape, onions,
peas, cabbage, and other garden plants; in the middle western states
and the prairie provinces on sugar beets. A native of Europe and
Northern Asia.

Adult. — A purplish-brown moth, with darker and paler bands; wing
expanse i inch. May and June.

Eggs. — Broadly oval, 3^^5 inch long, pale green; laid in clusters
(3-10) on the leaves.

Larva. — One inch long, dark with a white stripe down the back and
one on each side, marked with many black and white tubercles.

In Colorado the first brood of larvae feed on pigweed and alfalfa in
June; the second brood appears in July, and sometimes injures beets;
the third brood about middle of August is most injurious. Most of
the larvae hibernate in the ground m long silken tubes.

Pupa. — The pupa is formed in early spring in the silken tube.

Greenhouse Leaf Tyer {PhlyctcBnia Jerrugalis Hbn.). — A serious pest
in greenhouses to violet, rose, carnation, and other plants; and outdoors
to beet, celery, lettuce, sweet pea and other plants. It ties up con-
tiguous leaves by webs and feeds within, skeletonizing the leaves.
Widely distributed.

Adult. — A small moth, ^ inch wing expanse; fore wings light
brown and with blackish cross lines; hind wings grey with darker
margins.

Eggs. — Translucent, oval disks, 3^^2 inch long; laid in clusters of
8 to 12; hatch in 19-20 days.

Larva. — Three-fourths inch when full grown; greenish white with a
green line down the back and another on either side; head straw colored;
mottled. Full grown in 3-5 weeks; feeds mostly at night.

Pupa. — Formed within the webbed leaves.

Control. — Spray or dip the plants in solution of arsenate of lead as
soon as larvae are observed; hand pick infested leaves.

Crambid^ (Close-wings)

Root or Sod Web Worms {Cr ambus spp.).^ — In July and August
many small greyish moths with closely folded wings and with project-

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 211

ing mouth-parts (labial palpi) are common on grass lands and collect in
large numbers about lights. The caterpillars of these moths live in the
sod in silk-lined burrows among the roots of the grass, feeding upon
them. Corn is sometimes injured.

Adults. — Several species; yellowish- white wings with silver stripes,
bands, gold lines and other markings. Two broods. June-July.

Eggs. — ^Laid in grass land in June- July and again Sept.-Oct.;
oval, yellowish, ridged, 200 by each female; hatch in 6-10 days.

LarvcB. — Color varying from yellowish- white to pink to reddish;
surface tubercled with tufts of bristly hairs; form loose silken webs
and feed on the roots; full grown in 5 to 7 weeks; 3^^ to ^ inch long.
Hibernate in webs partly grown.

PupcB. — Cocoons formed often in the larval webs; 12 to 15 days.

Control. — Plow land early in autumn to prevent egg deposition;
plow early in spring; use trap-lanterns to catch the moths.

Cranberry Girdler {Cramhus hortuellus Hbn.). — (See Bull. 554, Bur.
Ent. U. S. Dep. Agr.) An injurious pest of cranberry vines, widely
distributed in United States and Canada. Its host plants are certain
grasses, Scirpus americanus, and cranberry.

The moths appear in June, and eggs are laid on the trash covering
the ground. These hatch in about 10 days. The larva feeds through-
out the summer and fall; when full grown it is about half an inch long,
with dark brown or black head, light amber colored thoracic shield and
tip of abdomen, and sooty-white body bearing many long and short
hairs black at the base. It forms cocoons in October-November, but
pupates following spring. Duration of pupal stage about 3 weeks.
The cocoon is composed of scraps of ground debris — bits of dead leaves,
bark, twigs, fine roots, grasses and sand — held together by strands of
silk. Its interior is lined with silk. Variable in shape, but usually
enlarged at one end.

Control. — Fall flooding after picking the crop; sanding; pruning.

Larger Com Stalk Borer {Diatraa saccharalis Fab.). — A serious pest
of Southern corn fields, originally of sugar cane. The caterpillar feeds
early in the season on the "throat" of the young corn, destroying the
growing tip, and later feeds as a borer in the lower stalk, where it
hibernates.

Adult. — A pale brownish-yellow moth, wing expanse of i}'i inches,
fore wings darker than hind wings and bear faint markings. Wings

212 ECONOMIC ENTOMOLOGY

held close to body when at rest. First brood appears April ist to
May 15th; and second brood May 15th to July ist.

Eggs. — Flat, scale-like, circular, ^{qq inch long, placed in rows
overlapping one another (2-25) on under side of a lower leaf; creamy
white at first; hatch in 7 to 10 days.

Larva. — Robust, dirty-white caterpillar i inch long, thickly covered
with roundish dark spots each with a single bristle; head and thoracic
shield brownish-yellow. Hibernating larva is unspotted. Summer
duration 20 to 30 days.

Pupa. — ^Light yellow changing to rich mahogany-brown, % inch
long. Pupation in the stalk; duration 7 to 10 days. (Consult Farmers'
Bulletin 634, U. S. Dept. of Agr.)

Pyraustid^

European Com Borer (Pyrausia nuhilalis Hbn.). — (Consult Bull.
178, Mass. Ag. Exp. St.) A pale yellowish or reddish brown moth of
about I inch wing expanse, introduced from Europe into Massachusetts,
whose larva bores into corn stalks. Its wild food plants are barnyard
grass, foxtail, pigweed, and its cultivated food plants are corn, hemp,
hops and millet. A possible serious enemy of corn.

Galleriid^

Bee-moth {Galleria mellonella Linn.). — Known also as Wax-worm.
Often a serious pest of bee-hives feeding on stored combs and honey,
and combs occupied by bees.

Adult. — Wings ashy-grey, hind part of fore wing bronze colored;
body brown, about ^g inch long. Appears April 15th to May 15th,
and again in July; lays her eggs in hives in crevices at night.

Eggs. — Elliptical, 3-^0 inch long, pearly white — hatch in 12 days.

Larva. — ^White; i inch long; feeds at night, and makes silk-lined
tunnels in the comb.

Pupa. — Formed in a tough cocoon on side of hive. Hibernates.

Life-history. — In the north two broods appear — the first in May,
the second in July-August, and under favorable conditions it requires
only 6 weeks from egg to adult.

Control. — Keep colonies strong; keep Italian bees; use well made
hives, fumigate with carbon bisulphide.

classification and description of common insects 213

Phycitid^

Apple Leaf Crumpler {Mineola indigenella Zeller).— A widely
distributed moth but injurious mainly in the Central States on
buds in early spring.

Adtilt. — Wing expanse ^^ inch; fore wings brown with patches
and streaks of silver. Emerges in June.

Eggs. — Laid in midsummer and hatch in about a week.

Larva.- — Three-fifth inch long when full grown; greenish brown, head
and thoracic shield dark brown; young larva brown, feeding on leaves
of tender shoots; construct crooked cornucopia-like cases of fras
and silk. Winters as half grown larva. Injures the buds in spring.
Full grown in June.

Pupa. — Reddish-brown.

Control. — Early spraying with arsenate of lead.

Apple Leaf Skeletonizer {Psorosina hammondi Riley). — Sometimes
injurious in Mississippi Valley especially on nursery stock, but not
common northward and eastward.

Adult. — A pyralid moth, }/i mch wmg expanse; fore wings glossy,
purplish-brown, marked with two transverse silvery grey bands.
Two broods a season. May-June and August.

Larva. — Small, Y2 iiich long, greenish or brownish, with 4 black
shining tubercles on back behind the head, and with a broad darker
stripe along each side of back. Feeding singly, or in groups, in July
and Sept.-Oct., on upper surface of leaves under a silken web, skeleton-
izmg them and giving them a rusty blighted appearance.

Pupa. — Formed among the leaves in a slight cocoon; pale brown,
}y'i inch long.

Mediterranean Flour -moth {Ephestia kuehniella Zeller) . A dull.- — A
pyralid moth, Ig inch wing expanse. Fore wings grey with transverse
black zigzag lines; hind wings greyish white with a darker border.
Both wings fringed. New generation every two months; lives about
a week (Fig. 133).

Eggs. — White, elongate oval; a female depositing as many as 200
eggs singly in flour, in cracks, and about machinery; hatch in about
a week.

Larva. — Cue-half inch long; white with fine black dots, sparsely cov-
ered with hairs. Feeds within a silken tube and spins a silken web,

214

ECONOMIC ENTOMOLOGY

matting the flour together and causing much damage. Full grown
in 40 days.

Pupa. — Formed in a cocoon; duration 11 days; cylindrical, reddish-
brown above and lighter below; a cluster of small hooklets at tip of
abdomen.

Control. — Fumigate with carbon bisulphide, carbon tetrachloride
or hydrocyanic acid gas; or better still raise room to high temperature
of 120-130° for 6 hours.

Fig. 133. — Mediterranean flour moth (Ephestia kuehniella) : a, moth; b, same
from side, resting; c, larva; d, pupa; e, abdominal segments of larva; a-d, enlarged;
e, more enlarged. {After Chittenden, U. S. Bur. Ent.)

Indian Meal -moth (Plodia inter punctella Hbn.). Adult. — A pyralid
moth, ^ inch wing expanse. Fore wings with outer portion red-
dish-brown with fine transverse markings, the middle copper and the
inner portion grey; hind wings grey. A new generation in about five
weeks.

Eggs. — Small, whitish; as many as 350 eggs laid either singly or
in clusters; hatch in 4 days.

Larva. — One-half inch long, whitish or pinkish, sparsely hairy.

Pupa. — Cocoon elliptical-cylindrical.

Gelechiid.^

Angoumois Grain Moth {Sitotroga cereal ella Oliv.). Adult.— A
small moth like a clothes moth; % inch long; yellowish-grey. Hind
wing dark grey, bordered with fine silvery fringe. Fore wing with a
black dot between base and middle.

Eggs. — Milky-white to pale red;3^^o i^ch long; bottle-shaped; 60-90
eggs hatching in 4 to 10 days.

J

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 215

Larva. — Body white, densely covered with bristles, tapering slightly
backward; head and antennae brown. Feeds within the kernel of grain.

Pupa. — One-fifth inch long, brownish, ovate; eyes black. Formed
within kernel.

Peach Twig Borer {Anarsia lineatella Zeller). — Destructive to grape
roots, peach and other trees in California and British Columbia and
troublesome also in the East.

Adult. — Dark grey; wings fringed with yellowish-grey, fore wing
marked with blackish-brown spots or streaks; expands 3^^ inch; several
broods each season.

Eggs. — Yellowish-white, elongate-oval; laid on bark of new twigs
near base of leaves; duration about 10 days.

Larva. — One-half inch long; dull reddish-brown with dark-brown
head; winters in silken cases beneath outer bark at base of new growth;
first brood attacks young growth, second brood attacks tips and fruit,
third brood the fruit.

Pupa. — Reddish-brown, }/i inch long; duration 10-12 days. .

Control. — ^Lime-sulphur just after buds begin to swell.

Palmer Worm {Dichomeris ligulella Hiibner). — (Consult Bull. 187,
Cornell Agr. Exp. Stn.) Adult. — A minute brownish-grey tineid
moth, expanding % inch; fore wing sprinkled with black scales,
and marked near middle with 4 black marks; hind wing fringed,
dusky. July. Hibernates as adult.

Eggs. — Probably laid in May, and hatch in 2 weeks.

Larva. — Skeletonizes the leaf and eats holes in the young fruit of
apple; a small caterpillar, \'2 inch long; brownish-green; head light
brown. Dorsal surface with two lateral and two dorsal whitish stripes.
June.

Pupa. — A small brown object attached to leaf by a few silk threads,
duration 10 days.

The Lesser Bud Moth (Recurvaria nanella Hbn.) , a native of Europe,
occurs in the eastern half of the United States and in Nova Scotia,
and attacks the buds of apple trees.

(EcOPHORIDiE

Parsnip Web Worm (Depressaria heracliana DeG.). — A European
pest introduced about 1873, feeding on wild carrot and on wild and
cultivated parsnips.

2l6 ECONOMIC ENTOMOLOGY

Adult. — Greyish buff or pale ochreous, marked with fuscous
spots; ^ inch wing expanse; July- August.

Eggs. — Laid in May on leaves, stem and on sheath of inflorescence.

Larva. — Pale yellow or bluish grey, marked with black tubercles
bearing bristles; head and thoracic plate bluish black; 3^^ inch long.
Larvae first web the flower-heads together and feed on the flowers
and unripe seeds; they then enter the hollow stems and feed on the soft
pith.

Pupa. — Formed within the hollow stem in a silken cocoon. Dura-
tion 2-3 weeks.

Control. — Spray carefully the flower-heads as soon as webbing is
observed with an arsenical, j

iEcERiiD^ = Sesiid^e (Clear Wings)

Peach Tree Borer {Synanthedon exitiosa Say). — (Consult Cir. 54,
Div. of Ent., U. S. Dep. Ag.; Bull. 170, Cornell Ag. Exp. St.) A native
insect occurring wherever peaches are grown east of the Rockies.

Adult. — A slender dark-blue clear-winged wasp-like moth. Male
moth with wings transparent and bordered with steel blue; expands
I inch. Female moth with fore wings blue and clothed with scales;
hind wings transparent resembling the male; a broad orange band
about middle of abdomen; expands 1)2 inches. July-September.

Eggs. — Minute, oval, yellowish-brown; and hexagonally sculp-
tured; truncate at one end; deposited on the bark near surface of
ground. Each female may lay from 300-400 eggs; hatch in about
10 days.

Larva. — One inch long when full grown, robust, yellowish-white,
with head and first segment white. Young larva bores into sap-
wood at or below surface of ground, and continues feeding well into
the fall, and after hibernating resumes feeding in spring, reaching full
growth from July ist-September. Exudation of gum mixed with
bits of bark and excrement.

Pupa. — Cocoon-like cell elongated, made of grass and bits of bark
attached with gum and threads of silk. Duration about 3 weeks.
One generation each year.

Control. — Probe or cut out the caterpillar in fall or early spring;
mounding up the earth about base of tree in spring; protect trunk
with paper or wire covering or netting (see Ohio Bull. 329).

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 217

Lesser Peach Borer {Synanthedon pictipes G. and R.)- — This native
insect occurs in most of the Northern States, in Ontario, and in some
of the Southern States, and frequently does considerable injury. The
larva bores as a rule above the soil level on the trunks and branches.
Winter is passed as a larva, the pupa is formed in the canker or wound,
and the moth emerges in June and July. About a month earlier than
S. exitiosa. Attack by this insect usually follows mechanical and canker
injuries.

Imported Currant Borer {Synanthedon tipuliformis Linn.) . A didt. —
A small clear- winged moth, ^i inch expanse; body black with a yellow
band about the neck, and three yellow bands across the tufted
abdomen; fore wings with a margin of blackish scales and a band
about one-third from the tip. June.

Eggs. — Small, brown, globular; placed in axils of leaves, or in
cracks of the canes.

Larva. — Bores into pith of cane and makes a long black tunnel in
it; when full grown 3^^ inch long, yellowish; head brown; numerous
tubercles on body. Half grown by winter; hibernates at bottom of
burrow; full grown in May.

Pupa. — Pupates in tunnel. Adult emerges in June.

Control. — Cutting out and burning the old and afifected canes in
fall or early spring.

Maple Sesian {Synanthedon acerni Clem.). — A serious borer in soft
and hard maple shade trees.

Adidt. — A beautiful wasp-like moth, with transparent wings;
body slender, yellow, banded trimmed with red, abdomen tufted.
May-June.

Eggs. — Laid in rough places on trunk.

Larva. — A white caterpillar, V2 inch long; head yellow; thoracic shield
light yellow. Burrows mainly just below the bark, often in develop-
ing tissue.

Pupa. — Formed at surface.

Control. — Apply soap-carbolic wash early in spring.

Squash-vine Borer {Meliitia satyriniformis Hbn.). Adult. — A clear-
winged moth, 13^^ inch wing expanse. Fore wings opaque, dark metallic
olive-green. Hind wings transparent, veins and fringe black. Abdo-
men with orange or black and bronze marks; legs orange; tarsi black
with white bands. June- July.

2l8 ECONOMIC ENTOMOLOGY

Eggs. — Oval, dull-red; ^^5 inch long; laid singly on stems of plant;
hatch in 1-2 weeks.

Larva. — Whitish, stout, i inch long; matures in 4 weeks; tunnels
in the main stem. Hibernates in the north in a cocoon in the ground.

Pupa. — Formed in tough silken cocoons in ground, in spring in
North; pupa dark brown with a horn on head and hook-like spines on
abdomen; % inch long.

Blackberry Crown Borer {Bemhecia marginata Harris).— Occurs from
Canada to New Mexico.

Adult. — A clear-winged moth, ij^ inches wing expanse; fore wings
with a transverse band on outer third; abdomen black, with four
bright yellow cross bands; last segment of female yellow, of male
black mixed with yellow. Aug.-Sept.

Eggs. — Oval, reddish-brown, He inch long; laid singly on under
side of leaves, about 140 by each female.

Larva. — At first white with a brownish head, hibernating under
bits of bark or just below surface of ground. In spring bores into
root girdling it; hibernating again in its burrow; in second spring bores
upward, and becomes full grown in July.

Pupa. — Reddish brown, ^ inch long, 25-30 days; formed in burrow
near surface of cane. Empty pupal skin usually protrudes from open-
ing when moth emerges.

Control. — Remove infested canes during spring and fall when
thinning and pruning, and burn them.

ToRTRiciNA Group
Eucosmidae

Apple Leaf Sewer {Ancylis nubeculana Clemens). — (Consult N. Y.
State Mus. Bull. 124; Bull. 435, U. S. Dept. of Agr.) Generally
distributed over the Northern States and Canada.

Adult. — A small white tortricid moth with brown markings; wing
expanse ^ inch. May- June.

Eggs. — ^Laid in June on under side of leaf; flat, oval-shaped, flanged,
minute, yellow; hatch in 8 days.

Larva. — One-half inch long; yellowish-green; head yellow; thoracic
shield darker with a black dot on each side; each body segment with
pale tubercles bearing a single hair. Hibernates in folded leaves on

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 219

the ground. Full grown in April. Total feeding period 5-6 months.
Spends the first 3 or 4 weeks of its life under a silken covering on the
under side of the leaf, afterward within a succession of folded leaves.
It folds the leaf along the mid-rib and forms its nest within.

Pupa. — Dark yellowish-brown, but head, eyes and wing shields
black mottled with yellow. Duration about 10 days.

Pig. 134. — Codling moth. A, adult moth with wings expanded; B, egg much
enlarged; C, half of worm-eaten apple; D, cocoon with empty pupa shell protruding;
E, cocoon with pupa enclosed; F, leaf and apple showing eggs of a codling moth;
G, caterpillar or "apple worm" enlarged; H, a, young apple just after petals fall;
b, cup beginning to close; c, too late to spray. {Montana Ag. Exp. St.)

Codling Moth {Carpocapsa pomonella Linn.). — This European insect
is probably the most destructive of apple insects and is practically
cosmopolitan (Fig. 134).

Adult. — A small greyish-brown moth, ^ inch expanse; fore wings
crossed by alternate irregular transverse waxy bands of brown and grey,
and with a large dark brown spot in the inner hind angle; hind wings

220

ECONOMIC ENTOMOLOGY

light silky brownish-yellow, darker toward the fringed margin.
Flies at night, about 1-2 weeks after the petals fall. Sometimes
emerges as late as July ist in northern districts.

Eggs. — A minute tliin scale-like white object, I25 inch in diameter,
at first transparent but later with a blackish streak. Each female
deposits 60 to 75 eggs, mainly on the leaves i to 3 weeks after the
blossoms fall; hatch in 5-10 days, or from 3 to 4 weeks after petals
fall; 60 to 80 per cent, of larvae enter the young fruit at the calyx end.

Larva. — At first whitish with distinct black tubercles on the body
and black head ; later the tubercles less distinct. When full grown larva

Fig. 135. — Larvse and ptipae of the codling moth in the bark.

is f 4 inch long, whitish or pinkish, head dark brown, tubercles indistinct,
thoracic and anal shields light brown. Matures in 3-4 weeks. Winters
as a larva within a white, tough, silken cocoon (Figs. 134 and 135).

Pupa. — Pale brown; ^2 inch long, back armed with transverse rows
of minute spines; within a cocoon; duration of spring pupae about 21
days, of summer pups about 15 days (July 3oth-August 14th in
Maine).

Life-history. — Winters as a full grown lar^•a within a cocoon on the
trunk, under bark, etc.; about the time of apple blossoming the larva
transforms to a pupa, and the moth emerges 15 to 22 days later. The
eggs are laid singly on the leaves, stems, and even fruit, where they
hatch in 7 to 10 days. The young larva feeds for a short time on the
leaves, but finds its way to the fruit which it enters usually at the calyx
end. It then makes its way to the core. When full grown in 3 to 4

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 2 21

weeks it makes its way out of the apple by a round hole and finds a place
under bark, etc., to make its cocoon. WTien a second brood occurs

^PRIL 1 MAT ! JUNE J JULY, [ AUGUST J St I

ft W-.l""!--^ i- f T 1 fl-^ -]

C^^C^^^^^T^^?^ ^' Over-Winter coei'onsfSee 'bLaJt

Fig. 136. — Chart showing life-history of the codling moth with suggested times of
spraying and banding in Utah. {After Hagon.)

Pig. 137. — The proper time to spray for the codling moth.

the moths emerge throughout August, and the second brood larvae
enter the apples chiefly from the side. In Northern New England and

ECONOMIC ENTOMOLOGY

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ECONOMIC ENTOMOLOGY

Canada, with the exception of Southern Ontario, there is but one brood
a year, with a very small percentage transforming to make a partial
second generation, but further south there are two or even three broods.
Parasites, Etc. — Trichogramma pretiosa, Trombidium on eggs;
Pinipla annulipes, Macrocentrus delicatus, Ascogaster carpocapsa,
Itoplectis marginatus, Hypostena variabilis and Tachinophyto on larvae;

Pig. 138. — Bud moth.

I, Adult moth; 2, larva; 3, pupa (dorsal view); 4, pupa
(ventral view). {After DuPorie.)

some beetles (Tenebroides corticalis) two species of ants, Lasius niger
and Solenopsis molesta, woodpeckers and chickadees. (Consult Bull.
142, Cornell Ag. Exp. St.; Bull. 41, 80, 97, 115, 189, 252, n. s., Div.
Ent., U. S. Dep. Ag.; Bull. 187, Ont. Dep. Agric.)

Control. — Spray with arsenical just after the blossoms fall, and again
in 3 weeks; destroy fallen fruit; band trees about July ist; fumigate
fruit-houses with sulphur to kill the moth (Fig. 136 and 137).

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 22$

Bud Moth {Tmetocera ocellana D. and S.)- — (Consult Bulls. 50 and
107, Cornell). — The caterpillar of this moth sometimes does serious
injury to the unfolding flower and leaf buds of the apple and other
orchard trees. Introduced from Europe, and occurs from the Atlantic
to the Pacific.

Adult. — A small moth with broad yellowish- white bands across ash
colored fore wings; % inch expanse; lives 2-3 weeks. Emerges in June
and July and deposits eggs (Fig. 138).

Eggs. — Flattened, disk-shaped, transparent; laid singly or in clusters
on the under surface of the leaves; hatch in 7-10 days.

Fig. 139. — Seasonal history of the bud moth in Quebec.

Larva. — Full grown larva 3^^ inch long, chestnut brown sparsely
clothed with light colored hairs borne on darker tubercles; head, legs
and thoracic shield dark brown or black, smooth and shining. Full
grown in June. Winters as half-grown larva in small oval silken cases
on bark of twig. Emerges in spring when buds are expanding and bores
into the bud and feeds for 6-7 weeks, latterly on the leaves tying them
together.

Pupa. — ^Light brown; i)^^ inches long; two rows of short blunt back-
ward pointing spines on back of abdomen; in a thin closely woven silk

15

226

ECONOMIC ENTOMOLOGY

cocoon within a tube of tangled leaves. Pupal stage lasts about
lo days.

Life-history. — Hibernates as a half-grown larva, and matures in
June; pupal stage lasts lo days and moth emerges in July to deposit
eggs. Young caterpillars feed on epidermis of under side of leaf and on
green tissue within a silken tube for protection. Toward the end of
September they leave their silken tubes and form oval silken cases on
the smaller twigs near the buds, where they hibernate (Fig. 139).

Fig. 140. — Pea moth: a, a full grown "worm" or caterpillar (enlarged);
b, adult moth with wings expanded (enlarged); c. adult moth with wings closed;
d, a group of five peas injured by the caterpillar of the pea moth.

Parasites. — Pimpla conquisitor , Bassus earinoides, Trichogramma
pretiosa {Pentarthron minutum), Opius sp., Microdus laticinctus.

Control. — Spray with arsenate of lead when buds are expanding,
when the leaves are expanded, and before and after blossoming.

ArgyroploceconsanguinanaWdX'i\im..\s, another bud pest of occasional
importance.

Pea Moth {Laspeyresia nigricana Steph.). Adult.— K small grey
moth % inch long. July (Fig. 140).

J

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 227

Eggs. — ^Laid in the growing pod; hatch in about 2 weeks.

Larva. — A small whitish slightly hairy caterpillar with pale brown
head and thoracic shield; about }2 inch long when full grown, feeding
within the pod on the green peas.

Pupa. — In a small oval cocoon in the ground near the surface.

Life-history. — Early in July the moths emerge from cocoons in
the ground, and begin egg-laying; larvae hatch out in about 2 weeks.
About the end of July the larvae emerge from the pods and spin small
oval cocoons near the surface where they remain all winter.

Control. — Sow early varieties; sow very late; deep fall plowing of
infested land; spray after blossoming with soap and Paris green and
repeat in 10 days.

Lesser Apple Worm {Laspeyresla primivora Walsh). — (Consult
Bulls. 68, Part V, and 80, Part III, Bureau of Entomology.) The
early work of this worm is similar to that of the Codling Worm,
only nearer the surface on the flesh just under the skin; the young
larvae hatched in August often eat on the surface of the fruit. Two
broods in the Northern States, and one in Quebec and northern Ontario.

Adult. — Ground color of fore wings brown with pale rusty-red
patches, and with grey, yellowish-white and blue oblique hnes; hind
wings dusky grey at base, shading to black at apex. Appears in early
June about the same time as the Codling Moth, and again in August.

Eggs. — Glistening white, minute, flat, oval, and covered with net-
work of irregular ridges. Deposited on both sides of leaves, but on
upper surface of fruit, stems, etc; hatch in 4-6 days.

Larva. — Full-grown larva 3^^-)^ inch long; reddish flesh-colored
above, lighter below; head brown; thoracic shield yellowish, transparent;
anal plate brownish, with a brownish comet-like structure on the
caudal curvature, and with an anal fork; mature in June and July.
Many of the second brood larvae enter the fruit on the side. Time
in fruit 2-4 weeks; larva in cocoon before pupation 7-8 days.
Larvae of second brood winter over.

Pupa. — ^Pupation in spring; cocoon densely lined inside with whitish
silk; pupa brown, 3^^ inch long; pupation stage about 10 days. Empty
pupal case usually attached to cocoon.

Control. — As for Codling Moth but spray again in August; destroy
hawthorns in vicinity.

2 28 ECONOMIC ENTOMOLOGY

Laspeyresia molesta Busck. — A new species found injurious to
peach in District of Columbia.

Clover Seed Caterpillar {Laspeyresia inter stinctana Clemens). —
(Consult Bull. 134, III. Ag. Exp. St.) Injures heads of red clover,
white clover and alsike.

Adtdt. — A silky dark brown moth, expanding about )^ inch; fore
wings with 8 or 9 silvery markings along the front margin, and 2
curved markings on hind margin forming two crescents when wings
are closed; hind wings dark brown with pale fringes. Probably three
broods each season. May-June ; July ; Aug .-Sept.

Eggs. — At first green, later yello wish- white ; shghtly flattened
orbicular; hatch in 5 or 6 days; laid on young clover heads, or on
young stems and leaflets near the base.

Larva. — One-third inch long; dirty- white to orange; head dark brown
and polished; thoracic shield yellowish or dark brown with a clear me-
dian line; dorsal tubercles arranged in 2 pairs and bearing hairs; body
with several pale stiff hairs. Mature in 4 to 5 weeks.

Pupa. — Brown, 3^^ inch long. Cocoon oval, white, silken, usually
with bits of flower tissue and excrement attached. Spun in a clover
head or at surface of ground. Duration 14 to 30 days.

Control.— Cnt and store the clover crop early in June; do not allow
clover to run for more than 2 years.

Grape Berry Moth {Polychrosis viteana Clemens). — (Consult Bull.
223, Cornell and Bull. 293, Ohio). A serious grape pest causing wormy
grapes.

Adult. — A purplish-brown tortricid moth, 3^ inch expanse; wings
leaden-blue with dark spots. Two broods.

Eggs. — Minute, whitish and scale-like, laid on stems of flower clusters
or later on the green berries; hatch in 4-8 days.

Larva — ^Mature caterpillar, % inch long, dark green to purpUsh;
head light brown; thoracic shield black; body covered with many
faint spots bearing whitish hairs; 3 weeks.

Pupa. — Formed in a thin silk cocoon in a piece of leaf; light green-
ish-brown. Duration 10-14 days.

Life-history.— In June- July the moths appear and lay their eggs
in the blossoms and on young grapes. The young larvae feed on the
blossoms and young berries, webbing the clusters together. They
mature in 3 weeks and pupae are formed in cocoons made from bits

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 2 29

of leaf and lined with silk. Moths emerge in lo to 14 days in early
August. The eggs of second generation are laid on the berries, and the
larvae feed on the pulp and seeds. Sometimes there is a third generation.
Winter is passed in the pupal stage.

Cow/ro/.— Spray with arsenate of lead, 4 lb., Bordeaux 2:3 : 50, and
2 lb. dissolved soft soap just after blooming; in August, when the
berries are half-grown, or about 7 weeks after the grapes bloom, use
6 lb. arsenate of lead.

TcRTRiciD^ (Leaf Rollers)

Fruit Tree Leaf Roller {Cacmcia ar gyros pila Walker).— (Consult
Bull. 311, Cornell, Bull. 250, Ont. Dep. Ag.) A serious enemy of the
apple east of the Rockies. It attacks also pears and plums, and some
shade and forest trees.

Fig. 141. — Egg-masses of fruit tree leaf roller. FiG. 142. — Fruit tree leaf

Natural size. {After Caesar.) roller: a, female; b, male.

Naturaljsize. {After Caesar.)

Adult. — Front wings mottled with a rusty-brown shade and silvery-
white markings; hind wmgs light ashy brown without markings, ^ inch
wing expanse. Early July; one brood each year (Fig. 142).

Eggs. — Attached to upper side of twigs in small oval, flat, greyish
varnish-covered patches, about 100 eggs in each egg-mass, in July.
Hatch as buds are opening. Hibernate (Fig. 141).

Larvce. — At first are black-headed and green; tie together the young
leaves and blossoms with a silk web, later cut large irregular cavities

230 ECONOMIC ENTOMOLOGY

out of young fruit. Injured fruit falls or is deformed. The leaves are
also badly injured. Full grown in three weeks; about i inch long;
light green; head, thoracic shield and legs brown to black.

Pupa. — Formed within a rolled leaf, brownish; duration about 10
days.

Control. — Spray with lime-sulphur (32°) and lead arsenate (3 lb. to
100 gal. water) about May 15, June i and June 15; use Scalecide
(i to 15) just before leaf-buds burst to destroy the eggs.

Cherry Tree Tortrix {Caccecia cerasivorana Fitch). — A pest of
cultivated and choke cherries.

Adult. — A tortricid moth, expanding about an inch; front wings
ochreous yellow with irregular brownish spots and many transverse
pale blue bands. July-August.

Eggs. — ^Laid in flat gluey-covered masses on twigs mainly near the
ground; hibernate; hatch in spring.

Larvce. — Lemon-yellow, ^^ inch long; colony forms nest enclosed
in silk web. Mature in July.

PupcB. — Formed within the dirty ugly nest. Duration 10 to 14
days. Pupal skms project from nest.

Control. — Cut out and burn the nests before the moths emerge.

Oblique Banded Leaf Roller {Caccecia rosaceana Harris) .■ — Injurious
to leaves and buds of orchard trees and small fruits; widely distributed.

Adult. — A yellowish-brown tortricid moth with three oblique
dark bands across the fore wings; bell-shaped with wings folded; hind
wings pale yellow. End of June.

Eggs.- — ^Laid in flat patches on the bark where they winter.

Larvce. — Roll up and fasten together the young leaves within which
they feed; ^ inch long; yellowish-green; head and thoracic shield brown-
ish-black; two broods, one feeding in May-June, the other in July-
August.

Pupa. — A dark brown object formed in its silken shelter in folded
leaves.

Control. — Spray with arsenate of lead in early spring and July.

Caccecia scmiferana occurs on apple.

The Large Aspen Tortrix {Caccecia conflictana Walk.) occurred in
destructive numbers in Manitoba in 19 16— 17 on aspen poplars, although
it is usually a rare insect. According to Criddle the adult emerges in
July and lays flat masses of eggs on the leaves. The caterpillars eat

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 23 1

holes in the leaves and spin much silk. About the end of July they go
into hibernation resuming feeding in the spring and pupating in July.
The natural means of control are hymenopterous parasites, birds, and
sudden climatic changes in early spring.

Lesser Apple Leaf Roller (Peronea minuta Rob.). — Sometimes inju-
rious in Eastern nurseries, causing the leaves to become folded and
brown; also a pest of cranberry bogs.

Adult. — Small, ^^ inch wmg expanse; fore wings of summer brood
bright orange colored; of the autumn brood slaty-grey. Two or three
brooded. Hibernates.

Eggs. — Minute, disk-hke, yellow; laid on unfolding leaves.

Larva. — Feeds within a folded leaf for 3 to 4 weeks. Broods work
in May, July and September.

Pupa. — Small, 3>i inch long, brown; head with a knob-like projection;
within a silken web or cocoon. Duration 7 to 10 days.

Spruce Bud Worm {Harmologa Jumifcrana Clem.). — (Consult Bull.
210, Maine Ag. Exp. St. and Hewitt's Reports.) A destructive pest
of spruces in Northern United States, Eastern Canada, Manitoba
and Vancouver.

Adult. Fore wings brown, varied with short dark brown striae;
hmd wings dark fuscous. July.

Eggs. — Pale green, scale-like, flat; laid in patches overlapping each
other. Hatch in about 10 days.

Larva. — When young pale green with a yellowish tint; head dark
brown, thoracic shield amber with two dots on posterior margin; hairs
half as long as thickness of body 3^^ i^ich long. Just before last moult
uniformly rust-red brown, and head and shield black. Full grown
larva with thick stout body tapering from middle to end; head not
quite so wide as body, and dark brown.

Feeds on needles of terminal shoots, often separating them at base
and spinnmg a silk thread about them and the bud scales. Hibernates
among the terminal shoots, becoming full grown the following June-
July.

Pupa. — Thick; thorax swollen; pale brown color striped with brown;
antennae and legs dull tan color.

Parasites. — Winthemia fumiferance, Pimpla Inquisitor and P. con-
quisitor, Meteorus trachynotus, Conoblasta fumiferancB, Mesochorus
diversicolor, Epiurus innominatus.

232 ECONOMIC ENTOMOLOGY

Strawberry Leaf Rollers {Ancylis comptana Frohl and Caccecia ohsole-
tana Walker). — These two tortricids often do injury to strawberry
leaves by rolling and destroying them. They may be controlled by
spraying the plants with a solution of lead arsenate (5 lb. to 100 gal.
water) within a week after the first appearance of the Moths.

Heliozelid^

Resplendent Shield Bearer (Coptodisca splendor if erella Clem.). —
Sometimes a serious pest in orchards. Found from Maine to
Minnesota.

Adult. — A small brilliantly colored golden-headed moth; fore wings
leaden grey and lustrous at base, outer portion golden with silver and
dark brown streaks; hind wings rich grey with long yellowish fringe;
antennae brown tinged with gold. May-June.

Eggs. — ^Laid on leaves.

Larva. — Small, 3^^ inch long, legless, light yellowish brown; head dark;
makes an irregular dark blotch mine )^ inch in diameter, in the leaf.
When full grown in July it cuts out a portion of the mine and forms a
seed-like yellowish shield, which is attached to bark. A second brood
in September, and in October the seed-like pupa case is formed.

Pupa. — In an oval, disk-shaped seed-like case. Hibernates.

Plutellid^

Diamond-back Moth {Plutella maculipennis Curtis). — A widely
distributed insect in U. S. and Canada. The caterpillar occasionally
attacks the leaves of turnips and cabbages, and does considerable
injury.

Adult. — A slender moth of a general ashy-grey color with white
marks on the back, diamond-shaped when wings are closed; % inch
wing expanse.

Eggs. — Minute, scale-like, greenish white or yellowish, laid singly
on lower surface of leaves.

Larva. — ^A minute, active, dull green caterpillar with spindle-shaped
body and with a wriggling motion when disturbed; mature form ^0
inch long; feeds on the lower surface of the leaves; effects visible in July.

Pupa. — Slender, yellowish, 3^4 inch long, enclosed in a beautiful
white lace-like cocoon on the surface of the leaves.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 233

Probably two or more broods in a year in Canada; seven broods
at Rocky Ford, Colorado.

Control. — Broadcast 2 to 3 cwt. ground lime per acre on appearance
of moths on a dewy morning. Brush off caterpillars. Spray the
caterpillars with kerosene emulsion, care being taken to get the solution
on the under surfaces of the leaves.

Yponomeutid^

Apple Fruit Miner (Argyresihia conjugella Zeller). — Occurs in
western portions of Canada and the U. S.

Adult. — One-half inch spread; fore wings purplish-grey mottled with
brown, with a row of small white and brown dots on front margins and
a broad white interrupted band. May- June.

Larva. — Pinkish-white; % inch long; burrows in all directions
through fruit. Also on wild crab.

Pupa. — In white cocoon with open pattern, under bark or leaves.

White Cedar Twig Borer {Argyresthia thuiella Pack.). — Causes a
rusty appearance on white cedars along the Ottawa.

Adult. — A small pearly white moth with costal and apical brownish
spots; head and thorax white; antennae white with brown rings. Latter
half of June.

Larva. — Slender, olive green, brownish at anal end; head black and
shining; thoracic shield piceous; 3^^ inch long before winter sets in;
hibernates in mines made in the young twigs; renews growth at end of
May and is 3>'4 inch long when full grown in June.

Pupa. — ^No cocoon; formed in the mines.

The Apple Ermine Moth (Yponomeuta malina) and the Cherry
Ermine Moth (Yponomeuta padella L.) are destructive orchard pests
in Europe. They reached the U. S. in 1914 on nursery stock imported
from France into New York State, and were discovered in shipments of
ornamental shrubs and fruit seedlings into New Brunswick in 191 7.

The moths are small, about f-^ inch wing expanse; fore wings white
with black dots; hind wings grey and broadly fringed. The caterpillars
are about % inch long and vary in color from pale to greyish or greenish
brown. The moths fly during July and August; the eggs hatch in the
fall and the young larvae hibernate beneath the scaly covering formed
by the egg-masses.

234

economic entomology
Haploptiliid^

Case Bearers. — Two species of Case Bearers are found in apple
orchards: the Cigar Case Bearer, and the Pistol Case Bearer. They
do most injury to the young buds and blossoms.

I. Cigar Case Bearer {Haploptilia fletcherella Fernald).- — (Consult
Bull. Q3, Cornell Ag. Exp. St.; Bull. 80, Ft. II, Bur. Ent, U. S. Dep.

Fig. 143. — a. Cigar case bearers and their work on apple leaves; b, pistol case
bearer and its work on young fruit. Natural size. {After Caesar.)

Ag.) Adult. — A small greyish moth, expanding 1^ inch; wings
broadly fringed. June-July (Fig. 143, a).

Eggs. — Delicate light lemon-yellow; pitted; cylindrical; laid singly
on under sides of leaves; hatch in 10-14 days, about July 15th.

Larvce. — Orange colored; head black; feed as miners for 2-3
weeks within the leaf, then later in curved cases on the leaves. About

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 235

September 15th they migrate to the twigs where they hibernate in their
cases. About April 15th they attack the young buds, etc.; about the
end of May they make their characteristic cigar-shaped cases, within
which they feed on the leaves. About the end of June they change to
pupae.

Pupa. — -Light brown; duration about 10 days.

2. Pistol Case Bearer {Haploptilia malivorella Riley) .^ — (Consult
Bull. 124, Cornell Agric. Exp. St.) The life history of this species is
very similar to that of the Cigar Case Bearer, the habits of the larvae
differing to a slight extent (Fig. 143 h).

Adult. — A minute moth with brownish, heavily fringed wings and
covered with white scales, head and thorax white; abdomen whitish;
all parts dotted with brown scales. June- July.

Eggs. — -Cinnamon-rufous; like inverted tea-cups with strongly
ridged sides; July; egg stage lasts about a week.

LarvcB. — Never miners; make cases as soon as they begin to eat.
In September they migrate to twigs where they pass the winter in
small pistol-shaped cases. In spring they attack the buds and make
irregular holes in the leaves. About the beginning of June they
change to pupae.

Pupa. — Pupal stage lasts about 2 weeks.

Control. — Spray with arsenate of lead in early spring just before the
blossoms open and in July.

TiscHERiiD^ (Leaf Miners)

Apple Leaf Miner {Tischeria malifoliella Clemens). — The larva
forms trumpet- shaped blotches under the surface of the leaves.

Adult. — A minute moth expanding }i inch; wings broadly fringed.
Fore wings shining dark brown with a purplish tinge; hind wings
grey; head and antennae dark brown. May.

Eggs. — Small, greenish-yellow, blister-like, elliptical, }yio inch
long; attached to surface of leaf. Hatch in 8-10 days.

Larva. — A miner within the leaf; mature in 3 weeks. Larvae
of last generation hibernate in the fallen leaf.

Pupa. — Pupa formed within the leaf. Duration 8-10 days. Two
or three generations each season.

236 economic entomology

Lyonetiid^ (Leaf Skeletonizers)

Apple Leaf Bucculatrix {Bucculatrix pomifoliella Clemens). —
(Consult Bull. 214, Cornell.) Adult. — A small moth, }^ inch expanse;
fore wings whitish tinged with pale yellow and dusky brown. Hind
wings broadly fringed. Appears when leaves unfold.

Eggs. — ^Laid in May, singly on under side of apple leaves; elliptical,
Mo X H25 inch, greenish, iridescent; surface rough.

Larva. — One-half inch long, cylindrical, tapering at both ends;
dark greenish-yellow, with reddish tinge on anterior segments,
active. Full grown in July.

Pupa. — Cocoons dirty white, slender, }^ inch long; six prominent
longitudinal ridges; oblong, tapering at both ends; fastened to twigs
in groups, in September-October, etc. Hibernates in this stage.

Birch Leaf Skeletonizer (Bucculatrix canadensisella Chamb.). — A
serious pest of birches, skeletonizing the leaves.

Adult. — A small brown moth, about M inch long; wings crossed with
fine white bars.

Larva. — Slender, green; head brown; tapering slightly toward both
ends.

It spins a small round white moulting cocoon on the twigs or leaf,
and later spins a yellowish ribbed elongate cocoon within which it
pupates.

Control. — By parasites and by spraying with arsenical solution.

TiNEiD^ (Tineids)

Clothes Moths. — Three injurious species of Clothes Moths are rec-
ognized in America:

(i) Case-making Clothes Moth, (2) Webbing or Southern Clothes
Moth, and (3) Tapestry Moth.

I. Case-making Clothes Moth {Tinea pellionella L.). — So-called
because the larva makes a true transportable case. (Consult Circ.
36, Bur. Ent., U. S. Dept. Agr.)

Adult. — A small tineid moth expanding 3^^ inch; head and
fore wings greyish yellow; hind wings greyish white and silky.
June-August.

Eggs. — Minute whitish, placed directly on foocj material; hatch in
about 10 days.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 237

Larva. — A dull white caterpillar with head and upper part of neck
segment brown; living within its case; feeds on woolens, carpets, furs,
feathers, etc.

Pupa. — Formed within larval case; duration about 3 weeks. One
generation a year in the North.

2. Webbing or Southern Clothes Moth {Tineola biselliella Hum.). —
Two or more broods in the North; more common than the preceding
in the North.

Adult. — Fore wings pale ochreous. Female larger than the male;
lays 4c^5o eggs.

Eggs. — ^Laid among the threads of the cloth; hatch in 7 days.

Larva. — Constructs no case, but spins a silky cobwebby path
wherever it goes; full grown in 10 or more weeks. Feeding all months
of the year on woolens and furs. Not readily poisoned.

Pupa. — Cocoon stage 2 or more weeks.

3. Tapestry Moth (Trichophaga tapetzella L.). — Rarer and slightly
larger than either of the preceding.

Adult. — Head white, basal half of fore wings black; outer half creamy
and grey; hind wings pale grey. Expanse ^^4 inch.

Larva. — Burrows in food materials, lining them with silk — no other
protection than the galleries or burrows it makes. Feeds on carpets,
horse blankets, tapestries,, felting, furs, skins and woolen upholstering
of carriages.

Control. — Give clothes or carpets a thorough beating, spray with
benzine and expose to sun for some hours, and repeat frequently.

C0SSID.E (Carpenter Moths)

Leopard Moth (Zeuzera pyrina Linn.). — A serious pest of shade trees
in the East, especially of elm and maple. A native of the old world.

Adult. — A white moth with blue and black markings; female much
larger than male and a feeble flyer. Male with pectinate antennae;
wings semi-transparent and white with black markings; thorax with
six large and one small black spot.

Eggs. — Oval, salmon-colored, deposited either singly or in a large
mass in crevices of bark; hatch in about 10 days.

Larva. — White or pinkish, over 2 inches long when full grown;
numerous dark tubercles with hairs on body; head, thoracic and anal
shields brown. Bores along the pith, eating the wood at intervals,

238 ECONOMIC ENTOMOLOGY

with an occasional opening for the removal of fras, which is soon closed
with a web of silk. Both large and small hmbs when attacked fre-
quently break off. Nearly full grown by second winter.

Pupa. — Formed in the burrow in May of second year.

Control.- — Prune away and burn the smaller injured twigs or
branches; inject carbon bisulphide into the openings of burrows and
seal with wax or putty.

Carpenter or Goat Moth {Prionoxystus robinicB Peck.).— The cater-
pillar bores into maple, oak, ash, willow and locust trees, often
producing deformities.

Adult. — A large moth, wing expanse of female 3 inches, of male
2 inches. Color dark grey mottled with light grey. Front wings of
male darker, and hind wings ochre yellow. June and July.

Eggs. — Oval, 3^fo inch long; each female lays several hundred
eggs; dirty whitish with one end black; finely reticulated, sticky.
Laid in crevices about injuries. About July ist.

Larva. — A large white caterpillar suffused with rose red, 2)^^ inches
long; head brownish, jaws prominent and black; thoracic shield dark
brown in front; each segment with several minute brownish tubercles,
each bearing a hair; spiracles brownish; a dark-colored dorsal hne;
under side of larva greenish white; bad smelling.

Pupa. — Brownish, i)^ inches long; dorsal surface of abdominal
segments with rows of tooth-hke processes. Formed in a loose cocoon
at ends of galleries. Duration 2 weeks or longer.

The life-cycle is believed to occupy 3 years.

Control. — Trim away deformities; inject CS2 into borings and close
holes with putty or cement.

Nepticulid^

Serpentine Leaf Miner {Nepticula pomivorella Pack.). Adult. — A
minute, purpHsh-black tineid moth; head tufted; reddish-yellow; June.

Larva. — Small, dark-green caterpillars Ho inch long. Make a
narrow serpentine mine beneath surface of leaves of apple and pear,
first half of mine broader than second half. In late autumn the larvae
find their way to twigs by means of silken threads, where they spin
small oval brown cocoons % inch long resembUng Lecanium scales. In
May they transform to pupae.

Pupa. — Bright green.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 239

ORDER DIPTERA (FLIES)

Sub-orders and Groups

A. Adults without a frontal lunule; pupa and adult escape from larval skin
through a T-shaped opening at anterior end. — Sub-order Orthorrhapha.
B. Antennae long, with more than five joints. — Nematocera Group
(Fig. 144, A).
BB. Antennae short, usually 3-jointed; first anal cell narrowed. — Brachycera
Group. (Fig. 144)
A A. Adults with a frontal lunule; pupa and adult escape from larval skin
through a circular opening at anterior end. — Sub-order Cyclorrhapha.

Fig. 144. — Antennae of common Diplera. A, Xiphuria (Tipulidse). B,
Sargus (Stratiomyiidas). C. Stratiomyia (Stratiomyiidas). D, Culex (Culicidas). E.
Tabanus (Tabanidae). F, Leptis (Leptidag). G, Chrysops (Tabanidge). H, Anthrax
(Bombyliidse). /, Dasyllis (Asilidae). J, Bibio (Bibionidae). K, Gonia (Tach-
inidse). L, Pollenia (Muscidae).

Chief Families of the Nematocerous Orthorrhapha:

A. A distinct V-shaped suture on back of thorax; legs long and slender.
— TipulidcB (Crane Flies) p. 242.
AA. No V-shaped suture on thorax.

B. Veins and margin of wings fringed with scales. — CulicidcE (Mos-
quitoes), p. 243.
BB. Margin of wings not fringed with scales.

C. Anal veins wanting; Media vein wanting; tibiae without spurs.
— CecidomyiidcB (Gall Gnats), p. 245.
CC. Anal veins present and Media vein at least represented by a
fold. Costal vein does not extend beyond tip of wing.

240

ECONOMIC ENTOMOLOGY

D. Abdomen slender; wings narrow; antennae pulmose in
the males; wing veins strong near costal margin. — Chiro-
nomidce (Midges), p. 252.
DD. Abdomen short and thick; wings broad; antennae short
and non-plumose. — Siniuliida (Black Flies), p. 251.
Chief Families of the Brachycerous Orthorrhapha (Figs. 146-149);

A. Antennae of five or more segments, those beyond the second more or less
united. (Fig. 144, E).

Fig. 145. — Venation of a tipulid
{Tipida). (After Comstock.)

Pig. 146. — Venation of a tabanid
{Tabanus). {After Comstock.)

AA.

B. Alulets large, third joint of antennae without a style or bristle. —
Tabanidce (Horse Flies), p. 252.
BB. Alulets small; branches of Radius crowded together near the costal

margin.- — Straliomyiidce (Soldier Flies).
Antennae of four or five segments but the third joint not ringed.
B. Antennae long, clavate, 4- jointed; branches of Radius curving toward
costal margin. — Midaidce (Midas Flies).

Fig. 147. — Venation of Dixa. {After
Comstock.)

Fig. 148. — Venation of an asllid
{Erax). {After Comstock.)

AAA. Antennae of three segments; Radius four-branched.

B. Vertex of head hollowed out between the eyes; palpi present. —
Asilidcc (Robber Flies).
BB. Vertex of head not hollowed out; alulets small; beak prominent. —
Bombyliidce (Bee Flies).
Chief Families of the Cyclorrhapha (Figs. 151 and 152):

A. Adults non-parasitic; maxillae covered by upper lip; Radius 3-branched.

B. With a spurious longitudinal vein between Radius and Media; front
convex between the antennae. — Syrphidce (Flower Flies), p. 250.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 24 1

BB. With rudimentary mouth-parts; palpi wanting; antennae with dorsal
arista.— tE^^r/^o" (Bot Flies), p. 254.
BBB. With well developed mouth-parts; palpi present; head with a suture
above the antennae. — Superfamily Muscoidea.
C. Alulets small; eyes of males not contiguous; thorax without com-
plete transverse suture. — (Acalyptrate Muscids.)

Rli.

Miti

Fig. 149. — Venation of a leptid (Leptis).
{After Comstock.)

Fig. 150. — Venation of a syrphid
(Eris talis). (After Comstock.)

D. Subcostal or auxiliary vein ending in the costa and distinctly

separate from Radius I, or first longitudinal, which usually

ends near the middle of the wing. Anal cell present.

E. Oral vibrissae present; front bristly; R. nearly half the

wing length; cross veins not close together; yellow or

brown. — Scatophagidce (Dung Flies).

Fig. 151. — Venation of Thereva.
{After Comstock.)

Fig. 152. — Venation of a muscid
{Musca). {After Comstock.)

EE. Oral vibrissas absent; eyes large; first posterior cell (R5)
closed or narrowed in the margin; proboscis and ovi-
positor greatly lengthened. — Conopidw (Thick-headed
Flies).
DD. Subcostal vein absent, vestigial or incomplete; Radius I
usually ending in costa before middle of wing.
E. Discal and basal cells united; Anal cell absent. — Os-
cinidce (Grass Stem Flies), p. 260.

16

242 ECONOMIC ENTOMOLOGY

EE. Discal and second basal cells separated; anal cell
complete.
F. Oral vibrissa present.

G. Arista long plumose or pectinate above. —
DrosophilidcE (Pomace Flies), p. 260.
GG. Arista bare, pubescent or short plumose;
front bristly as far as middle, usually light
colored. — Agromyzidce (Leaf-miner Flies), p.
262.
FF. Oral vibrissae absent.

G. Subcostal vein abruptly bent forward before
the tip of Radius I; anal cell angular. Wings
pictured. — Trypetida (Fruit Flies), p. 264.
GG. Subcostal vein more or less fused with Radius
I; all three basal cells distinct, anal cell not
produced; antennae more or less elongate and
decumbent. — Psilidce (Rust Flies), p. 262.
CC. Alulets or calypters large; eyes of males often contiguous; thorax
with complete transverse suture. — Calyptrate Muscids.
D. Cell Radius 5 closed or more or less narrowed at the margin
of the wing.

E. Antennal bristle bare. — Tachinidce (Tachina-flies), p. 278.
EE. Antennal bristle bare near tip. — Sarcophagida (Flesh-
flies).
EEE. Antennal bristle pubescent or plumose to the tip.

F. Dorsum of abdomen bristly; legs elongate. —
Dexiidce.
FF. Dorsum of abdomen not bristly except at tip. —
Muscida (House-flies), p. 268.
DD. Cell Radius 5 widely open. — Anlhomyiida (Root-maggot flies),

P- 273-
AA. Adults parasitic; upper lip enveloped by maxillae as by a sheath. — Piipipara
(Sheep-ticks, etc.), p. 279.
(Consult Tech. Series, No. 22, Bur. Ent., U. S. Dep. Ag. on "The Structure
of Certain Dipterous Larvae, etc., " by N. Banks, 19 12)

TIPULIDiE (CRANE FLIES)

Meadow Maggots {Crane Flies or Leather Jackets). Adult. — Large
mosquito-like flies with very long thin legs, long slender bodies,
narrow wings and thread-like antennas. A transverse V-shaped suture
on the back of middle portion of the thorax (Figs. 145 and 153).

Larva. — When full grown about an inch long, dirty brown, and
footless; of a tough leathery texture; cylindrical; tapering in front and
blunt behind.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 243

Pupa. — No puparium; occupying small cells near the surface of
the ground in a vertical position.

Broods. — There are two broods each season. Larvae winter over
and change to pupae in late May. Adults soon appear and deposit
eggs from which hatch the maggots. These change to pupae and
adults in September when eggs are laid for a fall brood. The maggots
hatching from these eggs winter over.

Control. — Early fall plowing, draining, and rotation of crops.

Fig. 153.- — Tipula.

A, Larva; B, cast pupal skin; C, imago.
{After Folsom.)

Slightly reduced.

CULICID^ (MOSQUITOES)
Key to The Common Genera

A. Palpi in both sexes at least almost as long as the proboscis. — Anopheles.
AA. Palpi in both sexes less than one-half as long as the proboscis. — Aedes.
AAA. Palpi in the male at least nearly as long as the proboscis; in the female less
than one-half as long. — Culex.

This family includes several important economic genera, comprising
many hundreds of species. The more important of these are Culex
pipiens, C. pungens, Anopheles maculipennis , and Stegomyia fas data =
Aedes calopus.

House Mosquito {Culex pipiens Linn.). Adult. — A slender-bodied,
delicate fly with gauzy wings, the. veins bearing minute scales; deep
yellowish to dark brown; legs and beaks not banded; abdomen with
narrow whitish bands at the base of each segment. Hibernates as
adult (Fig. 154).

244

ECONOMIC ENTOMOLOGY

^SS^- — Laid at night or early morning on the surface of standing
water in masses of 50 to 400. Hatch in about 24 hours. *

Larva. — Large head with a pair of mouth-brushes and a tube at
opposite end of body for breathing, not over four times as long as broad;
antennae of moderate length with a branch about the middle, bearing
a tuft of hairs. Full grown in a week; dirty white, or yellowish.

Pupa. — A hunched object, floating just below the surface of the
water. Duration i to 3 days.

Number of broods limited only by conditions of temperature and
moisture.

Fig. 154. — The common house mosquito : a, male; 6, female. {U. S. Bur. Enl.)

Malarial Mosquito (Anopheles maculipennis Meign.). Adult. —
Dififers from Culex in being much larger, more slender and with larger
legs; wings longer, and more or less spotted with brown or black, and
carried flat on the back when not in use; palpi or mouth-feelers as long
as the beak in both sexes. (In Culex the palpi are short in the female.)
A common malaria carrier.

E'ggs. — ^Laid singly on surface of water; hatch in 24 to 48 hours.

Larva. — ^Larva lies flat on surface; tube very short; at first black or

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 245

grey, usually banded with white; later color harmonizes with sur-
roundings. Full grown in 7 to 10 days.

Pupa. — Like that of Culex but with shorter, more trumpet-shaped
breathing tubes; duration about 2 days.

Other species of Anopheles are: A. pundipennis and A. crucians.

The Salt Marsh Mosquito (^e(/e5.yo//fa7a«5Walk.), the Swamp Mos-
quito {A. syhestris Theo.) and the Irritating Mosquito (Mansonia per-
turbans Walk.) are commonly met with and are annoying.

On the western prairies the genus Aedes is most abundant. The
eggs are laid in late summer and hatch out the following spring in the
water of the melting snow. There is but one brood a year. The most
common species are A. spcnccrl Theob., A. fletcheri Coq., and A. cur-
rlei Coq.

CECIDOMYIIDiE (GALL MIDGES)

Hessian Fly (Mayetiola destructor Say). — (Consult Ent. Bull. 11,
Dep. Ag., Ottawa; Bull. 116, Ont. Dep. Ag.; Cornell Bull. 194; and

Fig. 155. — The hessian fly (Mayetiola destructor): i, adult female; 2, mature
larva; 3, puparium or " flax-seed "; 4, seed of flax. Enlarged about 8 times. (After
Criddle, Ent. Bui. 11, Dep. Agric. Can.)

bulletins by Webster and Marlatt.) An introduced pest from Europe
and one of the most serious enemies of growing wheat. Distributed
over the wheat regions of United States and Canada. Attacks also
oats, barley, rye, Agropyron spp., Bromus, Elymus and Agrostis (Fig.

155)-

Adult. — A small dusky 2-winged fly, l<^ inch long, about half the
size of a common mosquito; the female with a dull reddish tinge and
larger than the male; legs long; wings smoky-black, covered with fine
black hairs and obscurely fringed.

246 ECONOMIC ENTOMOLOGY

Eggs. — Spindle-shaped, reddish and i to 50 inches long; hatch in 4
to 12 days.

Larva. — A footless maggot, clear-white except for a greenish stripe
down the middle; last stage of larva passed in "flax-seed" covering,
and having a peculiar "breast-bone," a horny forked structure.

Pupa. — Pupa case deep rich brown, like small "flax-seeds;" pupa
rosy colored and with a pointed beak.

Broods. — ^Two generations in fall wheat regions, and one in spring
wheat regions. Criddle reports a supplementary summer brood in
Manitoba, the adults appearing from late June up to middle of August.
Pup£e develop which winter over. Webster (640) is of the opinion
that the Hessian Fly is two-brooded even in spring wheat sections.
Female lays a few, to 50 or more, eggs on upper surface of leaf about
last week in August, first week in September or later, according to
latitude, altitude and longitude; maggots hatch in about 4 days and
move down the leaf to the stem where they embed themselves within
the leaf -sheath. In about 3 weeks they change to "flax-seed" but
remain as larvae until the following May, when they change to pupae.
The flies emerge a few days later to lay their eggs for a new spring brood
on the leaves of spring cereals. The maggot stage lasts until the third
week in June, and the "flax-seed" stage until the third week in August
or later, when the flies emerge (Fig. 156).

Parasitized by Folygnotus, Merisus, Eupelmus, TetrasHchus, and
Entedon, all Chalcids.

Control. — ^Late seeding in fall on well prepared seed-bed; trap-
strips; destruction of all volunteer wheat; destruction of "flax-seeds"
at threshing; co-operation. Plowing the wheat stubble deeply immedi-
ately after harvest. (See Part IV).

Clover Seed Midge (Dasyneura leguminicola Lintner).— (Consult
Bull. I 34, 111. Agr. Exp. Stn.). A widely distributed pest of red and
white clover fields. Alsike, mammoth and alfalfa are uninjured.

Adult. — A minute 2 -winged fly,K2 inch long, with red abdomen and
long reddish-brown legs and antennae; head and thorax black; wings
transparent with dusky hairs. April-May and July-August.

Eggs. — Very minute, orange, smooth and transparent. Laid in
green flower-heads, hatch in about a week.

Larva. — A footless orange maggot, Hq mch long, and with nine pairs
of respiratory tubercles and a sternal spatula.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 247

248 ECONOMIC ENTOMOLOGY

Pupa. — Cocoon oval, 3^2 inch long, made of silk threads; pupa
pale orange; eyes brown; two short tubercles on front of head.

Life-history. — There are two broods each year. Eggs are laid in
May in the forming flower-heads. At the end of June and early July
(June 20 to July 8 in IlHnois) the maggots mature and drop to the
ground to pupate. The adult flies emerge when the second crop of
clover comes into bloom (July 15-Sept. i) and lay their eggs among the
blossoms. The maggots leave the ripe heads in autumn, and pass the
winter in the ground. In May the adult flies emerge to lay their eggs.
Afl'ected florets do not expand their petals and remain fresh and pink
until after maggot leaves the bud, eventually fadmg and withermg
without opening.

Natural Enemies. — Tetrastichus, Anopedius, Triphleps.

Control. — Cutting or pasturing clover before the 20th of June.

Clover Leaf Midge {Dasyneura trifolii Low.).- — A serious pest of
white clover, affected leaves folding upon a midrib with maggots
enclosed.

Adult. — Smaller than the Clover Seed Midge, but very similar in
color and markings. Abdomen is darker, due to the large dorsal bands
of black scales.

Eggs. — Colorless soon becoming orange, cylindrical and slightly
curved; very minute; several eggs usually placed together between folded
leaflets near the ground.

Larva. — White at first, orange later; J25 inch long. Leaflet remains
folded in half along the midrib.

Pw^a.— Cocoon oval and about ^{5 inch long; pupa orange, with
blackish eyes and a darker median ventral stripe.

Life-history. — Probably four broods, each requiring about a month.

Control. — Pasturing or cutting frequently.

Rose Midge (Dasyneura rhodophaga). — An introduced pest of green-
house roses and often does serious injury. It is known also as the
Reinberg Fly by florists. The larvae "feed inside the flower and leaf
buds, preventing and distorting their growth, and soon causing them
to turn brown and then to blacken and die." Several generations.

Adult. — A 2-winged fly with long delicate legs; 3'^o inch long.

Eggs. — Cylindrical; laid at bases of the flower and leaf buds. Hatch
in 2 days.

Larva. — One-twelfth inch long and legless; mature in one week;

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 249

drops to the ground, burrows beneath the surface and spins a
silken cocoon.

Pupa. — Pupa within cocoon; duration one week. Hibernates.

Control. — Frequent fumigation with tobacco to kill the adults.

Grape Blossom Midge {Contarinia johnsoni Sling.). — A pest in the
Chatauqua grape belt of New York.

Adult. — A midge ifg inch long, with yellowish body and straw
colored legs. End of May.

^i,^^- — Minute, grey, elongate, curved; about 25 laid in each bud
which becomes swollen and yellowish and reddish when maggots
begin to feed.

Fig. 157. — The wheat midge {Diplosis trilici): a, female fly; b, male fly; c, larva.
Enlarged. {After Marlale, U. S. Bur. Ent.)

Larva. — Whitish to yellow-orange; }^2 inch long; passes the winter
in a small oval silk-lined earthen cocoon about 6 inches below surface
of ground.

Pupa. — Formed at end of April.

Control. — Spray with Black Leaf 40 just as buds of early varieties
begin to open, and again a week later.

Wheat Midge {Diplosis = Contarinia, tritici Kirby). — A European
pest, destructive to wheat, introduced probably by way of the Province
of Quebec (Fig. 157).

Adult. — A minute orange-yellow fly Hq inch long, smoky-tinged on
the back above the wings. June-August.

250 ECONOMIC ENTOMOLOGY

Eggs. — Minute, cylindrical, pale red; laid singly or in clusters in
crevices of wheat heads in June and hatch in about a week.

Larva. — A short oval orange-yellow maggot, ^{2 inch long; as a
rule it leaves the head after feeding for 3 or 4 weeks and goes into the
ground where it remains in a mustard-seed-like cocoon.

Pupa. — Pupa case small, about the size of a mustard seed, in the
ground; formed in June shortly before the emergence of the adult.

Broods. — At the end of June the adult flies lay their eggs in the
crevices of the wheat head; the eggs hatch in about a week, and the
larvae feed on the milky juices of the developing kernels for about 3
or 4 weeks; some descend to the ground where they form minute
puparia which remam until the following June; others remam and are
carried out in the screenings at threshing time. Only one brood a
year.

Control. — Burn or feed screenings; plow stubble deeply after harvest;
rotation of crops; sow wheat early. Dry weather unfavorable and
moist weather favorable for the development of the insect.

SYRPHID^ (SYRPHIDS OR FLOWER FLIES)

The Syrphids or Flower Flies are most valuable enemies of many
injurious forms of insects. They are usually bright colored and they
feed upon the pollen and nectar of flowers. Their maggots are often
found in colonies of plant-lice, upon which they feed. Some syrphid
larvae live in filth and are known as "rat-tailed maggots."

C. L. Metcalf ("Syrphidae of Maine," Bull. 253) notes five types of
Syrphid larvae:

1. The Aphidophagous type with body narrowed anteriorly, sub-
cylindrical and flattened ventrally {Allograpta and Syrphus);

2. The boring type, with body nearly cylindrical (Merodon).

3. The short-tailed filth-inhabiting type {Syritta).

4. The rat-tailed filth-inhabiting type {Eristalis).

5. The Microdon type, with body hemispherical in form.
Aphid-feeding species are Syrphus americanus, Allograpta obliqua,

SphcBropnoria cylittdrica, Didea fasciata, S. stanthostomus (Fig. 150).

The following genera live, in larval condition, in decaying vegetable
or animal matter: Eristalis, Platychirius, Orthoneura, Criorhina,
Syritta. (Consult "Syrphidai of Ohio" and "Syrphidae of Maine" by
Metcalf.)

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 25 1

A few forms are injurious in the larval stage. The Corn-feeding
Syrphid Fly {Meso gramma politus) feeds on pollen grains and at the
axils of the leaves of corn, producing a wilting and browning of the
lower leaves. It has been reported from several states.

Merodon equestris and Eumerus strigatus are pests of the onion,
narcissus and amaryUis. The larvae burrow into the bulbs.

Certain species, Eristalis spp., produce myiasis in man and some
of the domestic animals. The eggs are laid, singly or in masses, on or
near the food upon which the larvas feed, the exact location and number
depending upon the habits of the species. "They are chalk- white,
shiny, elongate-ovate or subcylindrical with rounded ends, J-^s inch
long and ^^^5 inch wide. Under the microscope each egg may be seen
to be delicately and beautifully sculptured "

The larvae vary also according to the habits of the species. They
are "headless, footless, blind creeping maggots." They breathe by
spiracles near the fore and hind ends of the body. They are \<2, inch
long when full grown.

Narcissus Fly {Merodon equestris F.). — A ser'ous pest of narcissus
and daffodil bulbs in British Columbia.

Adult. — A fly resembling the house-fly; March-September, most
common in May, when it begins to breed.

Eggs. — ^Laid in the centre of crown at surface of the ground.

Larva. — Found in centre of bulb which is often destroyed. Leaves
bulb in February and pupates 3-^ inch below the surface of the ground.
Three-fourth to i inch length.

SIMULIIDiE (BLACK FLIES, BUFFALO GNATS, TURKEY GNATS)

Several species of Simulium are very troublesome pests in our
northern woods, occurring in immense numbers in the vicinity of
running water. The females have well developed piercing and sucking
mouth-parts and their punctures are painful, with effusion of blood.
Black Flies have stout black humped bodies and are small, not more
than 1^ inch in length. They are most numerous in early spring and
are considered by travellers worse pests than mosquitoes. They are
active in the day-time, especially in bright sunshine.

The eggs are laid in patches on stones or other objects under running
water. The larvae are aquatic and gregarious; they are long and slender,

252 ECONOMIC ENTOMOLOGY

more or less cylindrical in shape, provided at the posterior end with a
disk-like sucker fringed with hooks wherewith they attach themselves
to the rocks. At the anterior end are two fan-shaped organs for secur-
ing food, and behind these on the ventral side is another sucker. The
pupa is formed within a boot-shaped cocoon, and is provided with two
tufts of respiratory filaments on the thorax.

As a rule there are two or three broods in a season. The most
abundant species in the northeast are Simulium venustum, S. vittatum
and S. hirtipes, on the western Canadian prairies S. similis Mall.
S. pictipes is innoxious.

Control. — Smudges and fumes of pyrethrum as repellents; destruc-
tion of larvae by phinotas oil.

CHIRONOMIDiE (MIDGES)

{Ceratopogon spp. {Punkies). — These minute flies, known as "pun-
kies," ''no-see-ums" and ''sand-flies," are also very troublesome pests in
northern woods. They are blood-suckers and attack any exposed
part of the body. The larvae are thread-like and live in water or
in moist places. Dr. Riley states that the following species bite:
Culicoides guttipennis, the most common form; C. cinctus, C. sanguisuga,
C. stellifer, C. variipennis, and C. unicolor. Not much, however,
is known regarding the habits of the difi'erent species.

TABANIDiE (HORSE FLIES, BULLDOGS, CLEGS, BREEZE FLIES)

Common Genera:

A. Hind tibise with spurs at tip; third segment of the antennae with five rings;
second segment but little shorter than the first; wings with dark markings.
— Chrysops.
AA. Hind tibiae without spurs; third segment of the antennae with a well-
developed process. — Tabanus.

(Consult "Tabanidte of Ohio" by Hine)

Black Horse Fly {Tabanus atratus Fab.). Adult. — A large fly with
broad and slightly flattened "body and large and depressed head; last
segment of antennae annulate and without stylet; females with power-
ful piercing mouth-parts (see p. 8); may transmit disease (Fig. 158).

Eggs. — Elongate, spindle-shaped; laid in large black masses of 500
on the leaves of grasses, sedges and other plants in marshy ground.
Hatch in less than 9 days.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 253

Larva. — ^Lives in the soil, mud or water; cylindrical, tapering,
2 inches long when full grown; yellowish-white with wide dark brown
bands at union of each two segments; prothorax with 2 lateral grooves
on each side; mesothorax with 4 longitudinal grooves on each side;
metathorax and abdominal segments like mesothorax. Carnivorous.
Hibernates (Fig. 159).

Pupa.— The pupal stage lasts only a few days; i}i inches long;
brownish yellow; lives beneath surface of the soil.

Fig. 158.-

-The black gad fly.
{After Carman.)

Enlarged.

Fig. 159. — The larva or
grub of the black gad fly.
{After Carman.)

Treatment. — ^Protect work horses with fiy-nets; smearing ears, with a
repellent solution composed of pine tar i gal., fish oil or crude carbolic
acid I qt., powdered sulphur, 2 lb.

On the western plains horse flies are very troublesome pests. The
most common forms are T. septentrionalis Loew, T. illotus O. S., T.
hirlulus Bigot, Chrysops moerens Walk., and C.fulvaster O. S.

254

ECONOMIC ENTOMOLOGY

CESTRID^ (BOT FLIES)

Common Genera and Species:

A. Costal vein ends at tip of R4+5, M1+2 is straight not reaching the margin,
and cell R5 wide open; squamae small, arista bare; ovipositor elongate. —
Gasirophilus (Fig. 160).
B. Wings with spots and smoky median cross band. — G. ifitestinalis.

Rz*3

R-t-s

Fig. 160. — Venation of wings of horse hot flies {Gasirophilus), 1, G. intestinalis;
2, G. nasalis; 3, G. hoemorrhoidalis.

BB. Wings without spots.

C. Posterior cross-veins (M-Cu) beyond the anterior cross-vein
(r-m) ; legs blackish brown. — G. hcemorrhoidalis.
CC. Posterior cross-vein opposite and nearer than the anterior cross-
vein. — G. nasalis.
AA. Costal vein ends at tip of M1+2; M1+2 with a bend; cell Rb much narrowed
or closed.
B. Facial grooves approximated below; cell Rs closed and petiolate. —
(Eslrus.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 255

BB. Facial grooves far apart; squamaj large, ovipositor elongate. — Ily-
poderma (Fig. 161).
C. Prothoracic band of yellow hairs, mesothoracic band of brownish
black hairs; media 3 sinuate; legs black with black hair; tips of
hind tibiae and tarsi yellowish-brown. — H. bovls.
CC. Thoracic band of hairs brownish; media 3 rounded; tibiae and
tarsi yellow; femora black.: — H. lineatum.

Fig. 161. — Venation

I, Hypoderma linealum; 2,

Warble Flies

The Striped Warble Fly {Hypoderma lineatum Villers). — (Consult
Bull. 5, Div. Ent., U. S. Dept. Agr.; Bull. 48, Minn. Agr. Exp. St.; Ont.
Ent. Soc. Rep., 1915; Que. Soc. Prot. Plants, 1918.) Causes much
loss to flesh and hides, and in lessened milk yield. Introduced from
Europe.

Adult. — A hairy fly resembling, a dark-colored bee; 3^^ inch long,
with yellowish- white hairs; abdomen banded above with black and
whitish stripes and terminated at apex with reddish-yellow hairs;
thorax with four lines often seem as white by reflected light. Mouth-
parts rudimentary and ovipositor blunt. Tibiae and tarsi yellow,
femora black. June-July (Fig. 162).

Eggs. — -Attached in spring and summer to hairs of cattle by a

256

ECONOMIC ENTOMOLOGY

peculiar clasping base, often several to a hair; 3^ ^5 inch long; dull
yellowish-white; narrow; ovoid.

Larva. — Dr. Cooper Curtice of Washington believed that the eggs
were licked into the mouth and the maggots bored through the wall of
the oesophagus, whence they gradually made their way to the tissues
along the back, causing warbles.

Miss Ormerod, of England, on the other hand maintained the
popular belief that the eggs were laid on the back, but Carpenter
of Ireland, and more lately Dr. Hadwen of Canada, have proven fairly

Pig. 162. — The striped warble fly {Hypoderma linealum). Enlarged. {After

Hadwen.)

conclusively that the eggs may be laid on almost any part of the
body of the animal, and that the maggots bore into the skin where
lesions and swellings are produced. They finally make their way to
the back where the warbles are formed.

Full grown maggots are greyish-white and nearly an inch long.
When mature they make their way out through the minute opening,
drop to the ground and bore an inch or so below the surface, where they
change to pupae. Four stages of larva; duration 9-10 months.

Pupa. — Puparium dark brown. Duration 3-6 weeks.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 257

The Ox Warble Fly {Hypoderma bovis DeG.).— This bot-fly is also
European and is found in several provinces of Canada and in several
states. It is more dreaded by cattle than lineaium, and causes much
panic due largely to the insect's persistence and manner of egg-laying.
More robust than H. lineatum. Body hairs yellow, except those on
scutellum and base of abdomen which are yellowish-white, and at apex

Fig. 163. — The ox warble fly {Hypoderma bovis). Enlarged. {After Hadwen.)

of abdomen which are bright lemon yellow (see Table given above
for structural differences between bovis and lineatum) (Fig. 163).

The adults of H. bovis appeared in B. C. from May 31st to August
2d as extremes (Hadwen). Carpenter says that most of the maggots
emerged from May 2 7 th to June 1 7 th. The pupal period has an average
duration of about 35 days varying according to temperature. One
egg is laid at a time, often when the cattle are running, besides not

17

258

ECONOMIC ENTOMOLOGY

SO many laid about the hoof as with lineatiim. SwelHng is more rounded
and more raised than that of lineatum, and exudes less serum.

Control. — When practicable dip every lo days and treat the larvae
with arsenic. Remove the larva from the warble in spring.

Larvae of a species of Uypoderma have been obtained from the
backs of horses.

Box Flies

These flies are probably of European origin but little is known
of their introduction.

Horse Bot Fly {Gastrophilus intestinalis DeG. = equi Fab.). Adult.
— A large brownish hairy bee-like fly, % inch long; head brown with

Mil^Sii.

■"T 2.

1/

Fig. 164. — Larvce of horse bot flies: i, G. hcemorrhoidalis; 2, G. inleslinalis; 3, G.
nasalis. {After Dove, Bur. Ent., U. S.)

three rows of black spots; wings with dark spots or bands; abdomen brown
with spots and conical. July-August.

Eggs. — Yellow, conical, attached by female without alighting to
hairs of fore-legs, shoulders and under side of body; |f 6 inch long;
hatch most readily lo to 15 days after deposition, with the aid of
warmth, friction and moisture.

Larva. — ^Licked into the mouth of the horse, thence into the stomach,
where it attaches itself to the wall. Remains in stomach 8-10 months.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 259

In spring it escapes in the droppings to the ground and Ijores an inch
or two below the surface where it pupates (Fig. 164).

Pupa. — Duration 30-40 days.

Chin or Nose Flies {G. nasalis Linn. andG. hcemorrhoidalis J^lnn.) . —
These flies are a serious annoyance to horses in the West. They have
bands of whitish, black and orange-red on the abdomen.

The eggs of G. nasalis are yellowish; laid on the hairs of the throat.

Parker (191 6) records the egg-laying of G. hcemorrhoidalis, the red-
tailed bot fly. The egg is black, barnacle-like and stalked, and is in-

FiG. 165.

-An effective leather fringe device to protect horses from the nose and
red-tailed bot flies. {After Dove.)

serted on the hairs of the lip and nostrils by the stalk. The "striking "
of the fly causes a sharp pain and excites a nervous uncontrollable
fear in the horse.

Control. — Administer three or four 4-oz. doses of turpentine,
followed finally by an ounce of powdered aloes; stable horses in day
time; groom carefully so as to kill or remove the eggs; use fly-nets of
loosely dangling cords for G. equi, and wire-screen muzzles, leather
nosebands cut into narrow strips or provided with canvas flaps for
G. nasalis and hamorrhoidalis (Fig. 165).

26o ECONOMIC ENTOMOLOGY

Sheep Bot Fly {(Estriis ovis Linn.). Adult. — A dull-yellow fly a little
larger than the House-fly and covered with minute spots; abdomen
with five rings, velvety and variegated with dark-brown and straw
color. Antennae small ; eyes purplish-brown ; ocelli three on top of head ;
no mouth; wings transparent extending beyond body ;alulets large cover-
ing the poisers. June-August.

Eggs. — Deposited in nostrils of sheep; hatch almost at once.

Larva. — Maggot works its way up the nasal passages until it reaches
the frontal sinuses, the cavities between and above the eyes. There
it attaches itself and feeds on the mucus present. Young is creamy-
white, with two brown spots, spiracles on last segment; full grown mag-
got darker, particularly posteriorly; two small hooks on head; small
rounded spots on sides of each segment. When mature, maggot passes
down the nasal passages and falls to the ground, which it enters
to pupate.

Pupa. — Puparium smooth, hard, and black, tapering toward
head; duration 40-50 days.

Control. — Apply tar to the nose; furnish a shed for the sheep or a
plot of plowed or dusty ground.

DROSOPHILID.S (POMACE FLIES)

Pomace Fly {Drosophila ampelophila Loew.). — This small fly breeds
in decaying or over-ripe fruit, and is a common pest about fruit-stores.
It is also suspected of being a typhoid-transmitter. The adult is a
small light-brown fly with bright-red eyes; the maggot is white and
about }'4 inch long; the pupa is yellow or brown with two long horn-
like breathing tubes at anterior end. The front tarsus of the male
has a comb of black spines on its upper side near the tip.

OSClNIDiE (GRASS STEM MAGGOTS)

Wheat Stem Maggot (Meromyza americana Fitch).^ — (Consult Bull.
42, Bur. Ent., U. S. Dep. Ag.) Adult. — A slender fly; yellowish-green,
I5 inch long, with 3 dark stripes running down the back; femora of
last pair of legs abnormally developed; eyes golden-green (Fig. 166).

Eggs. — About 1-^0 inch long, and glistening white.

Larva. — A watery-green footless maggot, }4, inch long, tapering to-
ward front end and broader posteriorly.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 261

Pupa. — Pupa-case translucent pale green; pupa greenish and } e inch
long.

Broods. — Probably three generations occur each season. The
eggs are laid in September-October on fall wheat. The maggots
eat down into the stem where they remain all winter. In early spring
they assume the pupal stage, and about the first of June the adult
flies appear. This brood matures
about August ist, when flies again
appear. This third generation ma-
tures at the end of September and
the beginning of October, when the
adult flies escape to lay their eggs.
Besides wheat, rye, barley, and
oats, this insect attacks timothy,
couch grass, Elymus, Poa, and
green foxtail.

Control. — Grain stacked or
threshed; straw stacked or burned;
burning of stubble when practicable.

Meromyza nigriventris Macq.
and Cerodontha femoralis Meig.
have been recorded as doing injury
in Montana.

American Grass Stem Maggot
{Oscinis carbonariaLoew .) . Adult. —
A black or yellowish fly, resembling
a minute house-fly, ifs inch long.

Larva. — A yellowish-white

slender maggot with two distinct p,^ i66.-The wheat stem maggot:

hook-like jaws and two knob-like a< adult; b, maggot; c, pupa; d, pupa

,11, . r i.1- within the stem; e, parasite. (After

processes on the last segment 01 the i^^„„g^ )
body; ^f 2 inch long.

Pupa. — Pupa- case cigar-shaped and pale chestnut brown.

Broods. — Similar in life-history to Wheat Stem Maggot. The
larva destroys the centre of the young shoot at the ground in the
autumn.

Other Species. — O. coxendix Loew. and 0. dorsala Loew. occur on
prairie grasses, sometimes very abundant.

262 ECONOMIC ENTOMOLOGY

Control. — Summer-fallow grass lands; prevent volunteer growth
in autumn.

PSILIDiE (RUST FLIES)

Carrot Rust Fly {Psila roscB Fab.).- — This fly is a native of Europe,
and the larva frequently does considerable injury to the roots of
carrots, celery and parsnips.

Adult. — One-sixth inch long, dark green, sparsely clothed with yellow
hairs; eyes black, and head and legs pale yellow.

Eggs. — Deposited by female about roots of host through cracks
in the ground.

Larva. — Maggot dark brown, ^fo inch long, slender, truncate
at posterior end; segments well marked, head small.

Pupa. — Puparium dark brown; anterior segment obHquely trun-
cate; \i, inch long; pupation in the earth.

Life-history. — (Consult Fletcher's Reports and Bull. 2>Zy U. S. Div.
Ent.) Winters as larva or pupa; adults appear early in the season;
summer generations develop in 3 or 4 weeks (Curtis); both flies
and maggots found throughout the warmer months; number of broods
uncertain.

Control. — Spray the carrots four or five times at intervals of a week
or ten days with kerosene emulsion, the first application at the time
of thmning; spread the earth in which carrots have been stored in the
poultry yard; sow late and practice rotation of crops.

AGROMYZID^ (LEAF MINER FLIES)

Marguerite Fly {Phytomyza chrysanthemi Kowz.). — (Mass. Agricul-
tural Experiment Station, Bull. 157.) Attacks compositous plants
and is especially injurious in the greenhouse. Occurs in the Northern
States, and has done considerable injury in B. C.

Adult. — A small greyish fly }{2 inch long, with a yellow stripe on
each side of abdomen; face yellow; antennae black; legs black with
yellow markings; rather inactive. Average length of generation about
;^T, days; several generations a season in greenhouse.

Eggs. — ^Laid singly in incisions between flesh and skin of leaf.
Hatch in 5 days.

Larva. — Burrows in the leaf, producing irregular whitish lines or

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 263

patches, often causing withering, also preventing flowering or reducing
the number of blossoms. Matures in about 17 days.

Pupa. — Formed in larval mine. This stage lasts about 14 days;
puparia dark brown.

Control. — A solution of Black Leaf 40 and Soap applied at intervals
of 10 or 12 days, as soon as first signs of operation of the insect.

Asparagus Miner (Agromyza simplex Loew.). — ^(Consult Bull. 66,
Part I, U. S. Bur. Ent.) Injures asparagus stalks, the maggot
mining beneath the epidermis, sometimes girdling the stem.

Adult. — A black two-winged fly; eyes and head prominent; wings
clear with }q inch expanse. Probably two generations, June and
August.

Eggs. — -White; deposited just beneath epidermis of stalk.

Larva. — -Milk-white; 3^^ inch long; footless, truncate posteriorly
and tapering anteriorly.

Pupa. — Puparium flax-seed-hke, red, i^f inch long; attached to slits
in epidermis of asparagus stalk near ground.

Control. — Pull up and burn infested stalks in spring; destroy
volunteer trap plants in late June.

Com or Spike-homed Leaf Miner (Cerodonta dorsaUs Loew.). —
(Consult Bull. 432, Bur. Ent., U. S. Dept. Agr.) This leaf-miner
has a wide distribution in the U. S. and feeds on a wide range of
cereal and grass plants. Three generations at least in Indiana.

Adult. — One-twelfth to 3^fo ii^ch long; proboscis, palpi, front,
antenn£e, legs, mesonotum and abdomen mostly yellow. Punctures the
leaves, in some of which an egg is laid. May in Indiana, but active
throughout the year in Pasadena, Cal.

£gg5.— Elongate, kidney-shaped, rounded at each end. Color
opaque white; }-qq inch long. Hatch in 3-12 days.

Larva. — ^Dirty-white; ^-q inch long; slender, nearly cylindrical;
mouth-hooks black; body segments plain; posterior ends truncate;
mines in the leaves and stem of host plant, frequently killing the parts
affected. Full grown in 9-24 days.

Pupa. — White at first, turning yellow and dark later. Duration
9-24 days. Hibernates (in Indiana).

Control. — -(i) Summer fallowing, (2) fall plowing, (3) burning dry
grasses along fence lines, roadsides, etc. in late fall and early spring.

264 ECONOMIC ENTOMOLOGY

TRYPETIDiE (FRUIT FLIES)

Common Genera (after Williston) :

A. Bristle on each side of front with a terminal leaf-like appendage. — Ceralitis.
AA. Front without such bristles; wings with colored markings not reticulate;
scutellum not with six bristles; fourth longitudinal vein not conspicuously
curved forward at its extremity.
B. Distal portion of wings marked with two hyaline indentations. Sepa-
rated by a curved or arched brown projection from the brown oblique
cross-band; body short; abdomen as broad as thorax; antepenultimate
section of fourth vein curved. — Epochra.
BB. Wings not marked as in B.

C. Coloring of body generally light, never black; cross-bands on
wings nearly transverse; cross-veins but little oblique. — Trypeta.
CC. Coloring of body black; wings with four very oblique black cross-
bands; cross- veins not approximated; scutellum with 4 bristles,
yellow. — Rhagoletis.

Mediterranean Fruit Fly (Ceratitis capitata Wied.). — (Consult Circ.
160, U. S. Div. Entomology.) Probably a native of the East Indies.
The appearance of this destructive insect in Hawaii has alarmed the
fruit-growers of the Pacific coast, and quarantine restrictions have been
enforced. It already occurs in Africa, Europe and Asia, in Australia
and in Brazil, and attacks nearly all kinds of fruits.

Adult. — An active fly about size of house-fly, ochre yellow color;
eyes reddish purple; a blackish blotch in centre of forehead where two
stout black bristles arise; thickened basal antennal joints yellow,
terminal segments black; dorsum of thorax convex, yellowish- white
marbled with shiny black blotches. Wings broad and semi-opaque
with extreme base blotched with ochreous or brownish yellow, the rest
of the basal area marked with black; beyond a broad, irregular, trans-
verse ochreous band blotched at extremity; another similar blotch
inside of costal vein.

Abdomen oval, with fine scattered bristles on upper surface, and
two rather broad transverse silvery white bands on basal half. Num-
ber of broods depends on temperature and food supply.

Eggs. — Glistening white eggs placed beneath skin of ripe fruit
by sharp extensile ovipositor. Eggs not all deposited at once.

LarvcB. — ^Begin feeding at once on the pulp, when mature (2-3
weeks) they leave the fruit and enter the ground, changing to puparia.

Pupa. — Duration 12-21 days.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 265

Control. — Cleaning up and destruction of all fallen fruits; covering
trees with netting; using a poison bait spray (Berlese and Mally).

Currant Fruit Fly [Epochra canadensis Loew.)- — (Consult Bull.
264, Maine Agr. Expt. St.) A common pest on currants and
gooseberries in Canada and the Northern States, and confined to the
Canadian, Transition and Upper Austral zones.

Adult. — Pale yellowish, slightly smaller and more delicate than the
house fly; eyes green, legs yellow, wings cross-banded; active and
restless. May and June. Mating period 2)2> days; preoviposition
period 6-10 days. One brood a year.

Eggs. — Elongate, oval, whitish, },^^ inch long; placed under skin
of fruit by long ovipositor. Female may lay about 200 eggs. Hatch
in 4-7 days.

Larva. — Burrows within the fruit, destroying seeds and kernel.
Infested berries show discolored spots, become deformed and usually
fall early. Matures in 3 weeks; J^
inch long, white with black mouth-
parts. Leaves the fruit and enters
the ground to pupate.

Pupa. — ^Puparium broadly oval
and straw colored, in the ground.
Hibernates. D uration lo-ii
months.

Control— kWov^ poultry to run ^^''- ]^l-~^ ^^"\^l^ white-banded

^ . -^ cherry fruit fly. Much enlarged.

among the bushes to pick up fallen {After Caesar.)

infested fruit; spray bushes with a

sweetened poison of sodium arsenite and diluted molasses to kill adult

flies at intervals of a week beginning early in May. A heroic but

effectual method is to pick entire crop of fruit and destroy it before

the maggots emerge.

White-banded Cherry Fruit Fly {Rhagoletis cingulata Loew.).
Adult. — A small blackish fly, smaller than the House-fly, % inch
long, expanding % inch; pale yellow spot on hinder part of thorax
and a yellowish stripe along each side of thorax; head yellow, eyes
gold-green; legs yellow, abdomen crossed with 3 or 4 white bands.
Wings with four brown cross bands, and a black spot at tip. June
(Fig. 167).

Eggs. — Egg-laying begins about 11 days after emergence of flies.

266

ECONOMIC ENTOMOLOGY

Eggs inserted under the skin of cherries; small, glistening white; ellip-
tical; hatch in about 5 days.

Larva. — One-fourth inch long, white or cream-colored, cyhndrical,
tapering. Twelve to 22 days in fruit; destroys the pulp. Leaves the
cherry when full grown.

Pupa. — Puparium formed just beneath the surface of the ground;
brown; hibernates.

Black-bodied Cherry Fruit Fly {Rhagoletis fausta O. S.). — (Consult
Bull. 227, O. A. C, 1915.) Adult. — Larger than preceding; black with-
out white cross-bands on the abdo-
men; head, eyes and legs similar to
those of cingulata but bands on wings
darker and differently arranged (Fig.
168).

Eggs and Larva. — Similar to
those of cingulata.

Pupa. — Puparium cream or straw
colored.

Control. — Spraying with sweet-
ened arsenate of lead solution (2
to 3 lb. arsenate of lead (paste), 40 gal. of water and i gal. of
cheap molasses) when the flies begin to emerge about June loth, and
again 10 to 12 days later.

Apple Maggot or Railroad Worm {Rhagoletis pomonella Walsh). —
(Consult Rep. Maine Ag. Exp. St., 1889; Cir. loi. Bureau of Ent.,
U. S. Dep. Agr.; Bull. 171, N. H. Ag. Exp. St.; Bull. 324, Cornell Ag.
Exp. St.; U. S. Dep. Ag., Bull. 9.) This maggot is a serious pest
of apples in N. E. districts. It is probably a native species, and
occurs widely in both the United States and Canada on apple, crab-
apple, haw, and huckleberry. Perhaps most common on sweet and
sub-acid varieties of apple.

Adult. — A small fly, a little smaller than the house-fly; blackish,
with yellow head and legs; eyes green; 3-4 white bands (3 in male
and 4 in female) across the abdomen; wings marked by four dark irreg-
ular bands. July and later, each female capable of laying 300-400
eggs; uses sharp ovipositor to puncture the skin of the fruit. Pre-
oviposition period may be as short as one week or less, but usually
longer than a week (Fig. 169).

Fig. 168. — A female black-bodied
cherry fruit fly. Much enlarged.
{After Caesar.)

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 267

Eggs. — Elliptical, yellowish, pedicellate, ^^q inch long; laid singly
just under the skin of the apple; hatch in 4-10 days.

Larva. — ^A small plump white legless maggot, l^ inch long; mouth-
parts with a pair of small black rasping hooks; caudal end truncate;

Fig. 169. — A female of the apple maggot fly {Rhagoletis pomonella). M uch enlarged.

{After W. H. Briltain.)

makes soft discolored trails and corky strands in the pulp; full grown
in 4-6 weeks, or when the infested fruit is ripe. • Infested apple usually
falls, and larvae leave the fruit i to 4 weeks later to enter the ground
(Fig. 170).

Fig. 170. — A parasite of the apple maggot (Biosteres rhagoletis). Enlarged.

W. H. Briltain.)

{After

Pupa. — -Puparium just beneath the surface of the ground in which
the pupa rests all winter, and in some cases the following year. Some
flies emerge in September from early pupae.

268

ECONOMIC ENTOMOLOGY

Life-history. — Hibernates as pupa in the ground; adults begin to
emerge in July, and appear irregularly later; maggots hatching from
the eggs tunnel in the flesh of the fruit, sometimes close to the surface.
They mature in 4-6 weeks, and make their way out of the apple to
the ground, the time (i to 4 weeks) depending on variety of apple
— a short time (3 days) in early apples. Infested fruit usually falls.
There is but one generation each year. " Some forms require an extra
year for the pupal stage" (O'Kane).

Control. — Apply arsenical or poison-bait spray in early July for
adults; collect fallen apples; allow hogs the run of the orchard.

Records

Locality

Emergence
of adults

Oviposition

Larval
period

Second brood
adults

Authority

Ithaca, N. Y. . .
Durham, N. H..

Bowmanville,

June IS

1910, July 9

191 1, June 26

1912, June 28

1913, July 10
191 2, July 6-

Aug. 20

1915, July 27
—Sept. 29

1916, July 18
-Sept. 18

July 4

July 4- Sept. 18

July 20

July 27-Sept. II
July 25-Sept. 12

July 4

(12-32 days)
30 days

more or less

Some flies emerge

in Sept,
None

Illingworth
O'Kane.

Ont.
Windsor, N. S...

4 weeks +

None

Brittain

MUSCIDiE (MUSCLDS)

Common Genera (Figs. 171 and 172):

A. Proboscis long, slender, directed forward, adapted for piercing; arista
pectinate (rays on one side only).

B. Palpi nearly as long as proboscis. — Hamatobia (Lypcrosia).
BB. Palpi much shorter than proboscis. — Stomoxys.
A A. Proboscis not elongate; labella fleshy and not adapted for piercing.

B. Arista plumose; hypopleurae with a vertical row of bristles; eyes bare;
vibrissal angle distant and above oral margin.
C. Thorax and abdomen with depressed yellow woolly hairs among
the bristles; sternopleurals arranged i : i. — Pollenia.
CC. Thorax and abdomen without such hairs; sternopleurals arranged
2:1; mesonotum distinctly striped; bright metallic. — Chryso-
myia.
BB. Arista plumose; hypopleura; without a row or tuft of bristles.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 269

C. Last section of fourth vein (Mi^.2) with a rounded angle. —
Musca.
CC. Last section of fourth vein curved forward, often slightly, beyond

/ d.dc anterior dorso centrals
aide •■ inner -
a. ia ■■ intraalar
h liumerals
p.h post "
* '\ps. presutural
Scute Hum hdc posterior dorso centrals
yp.ldc ■• inner ••
i.a. intraalar
pra prealar = anterior sa
sa supra alar
-.. sq. \ -( Lower squamar
\jj isq.\ \ ^^'\squamula thoracal is

■ ^ \5quamula a/aris

Vertical
-Ocelli

prbitals

• --•-

•---.-- \^

^Transi/erse
suture , ,

a. Ida.

...Pjdc

a.dc

— • •

>./)

2/4,..

}.^--

./^53,

■Ocellar

Antenna
r^lil^^-Vibrissal ndges
Oralmargin

Vibrissa
^Palpus
Proboscis

Fig. 171. — Dorsal aspects of the thorax, and frontal aspect of the head of a
muscoidean fly, with designations of the parts commonly used in taxonomic work.
{After Riley and Johannsen, Comstock Pub. Co., Ithaca, N. Y.)

its middle or at the tip, the cell broadly open; the first longitudinal
vein (Ri) ending beyond the middle of the wing. — Muscina.
BBB. Arista plumose; hypopleurae and eyes as in B; vibrissal angle, near
oral margin.

270

ECONOMIC ENTOMOLOGY

C. Mesonotum flattened behind the transverse suture; posterior dor-
socentral and acrostichal bristles inconstant and unequally
developed. — Phormia.
CC. Mesonotum not flattened behind the transverse suture; posterior
dorsocentral and acrostichal bristles well developed and constant.
D. Cheeks hairy; third longitudinal vein {Ri^b) spinulose at
base only. — Calliphora.
DD. Cheeks bare; third longitudinal vein (R4+5) spinulose.—
Lucilia.

.Trans verse sutur ,Post alar callus

Propleura-

Front coxa -^

Haltere

Hind coxa

Middle coxa-

Fig. 172 — ^Lateral view of the thorax of a muscoidean fly, with designations of
the parts commonly used in taxonomic work. {After Riley and Johannsen.)

House-fly {Musca domestica Linn.). — A cosmopolitan insect
dangerous to human life. A carrier for typhoid fever, tuberculosis,
dysentery and other diseases (Fig. 173).

Adult. — A two-winged fly with four black hnes on back of thorax;
bristle of antennae feathered; vein ending near tip of wing distinctly
elbowed; no bristles on abdomen except at the tip. Mouth-parts used
for sucking not for piercing, retractile; mouth-parts and feet specially
adapted for carrying micro-organisms. Each foot with two claws and
two sticky pads. Egg-laying begins 10-14 days after adult emerges
from puparium (Fig. 174).

Eggs. — Minute, glistening white, long ovoid, }^ inch long. Laid in
irregular small clusters. Each female lays about 120 eggs at a time

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 271

and may lay several times; hatch in about 8 hours in mid-summer.
Laid in horse manure, pig manure, and to a less extent in other manure,
human excreta, in decaying grain, moist bran, moist mixtures of hay
and grain from feed troughs, in excreta-soiled straw, decaying kitchen
refuse, rotting fruits, vegetables, in ensilage.

Fig. i73.^The common house-fly (Musca doynesticd) . Puparium at left; adult next;
larva and enlarged parts at right. All enlarged. {After Howard.)

Larva. — At first glistening white; two moults; duration about 5 days;
yellowish when full grown, slender in front and truncate behind; a
large hook above the mouth; active. Develops in horse manure
and other filth in substances more or less alkaline. ^

Pupa. — ^Puparium nearly cylindrical,
dark chestnut; duration 3-4 days.

Duration of Hfe-cycle 10-14 days. Prob-
ably seven to ten generations develop be-
tween April 15th and October loth. It
hibernates as larva or pupa in the South
but probably more commonly as adult in
the North. (Consult Howard's and
Hewitt's books on "House Flies.")

Stable Fly {Stomoxys calcitrans Linn.).
— Occurs in stables, yards, shady groves, dwellings, etc.

Adult. — Resembles house-fly, but has piercing mouth-parts; bright
golden tinge at front end of median, light stripe on thorax; six black lines
on thorax; dorsal surface of abdomen with a number of nearly round
dark spots. Bite severe but not poisonous. A carrier of disease;
breeds in moist straw and hay.

P e

Fig. 174. — Extremity of
tarsus: e., empodium; p.,
pulvillus in A, Bibio; B,
Musca.

272 ECONOMIC ENTOMOLOGY

Eggs. ^Laid in an irregular heap of about 100 on manure and gar-
bage; similar in form to those of House-fly; hatch in 2-3 days.

Larva. — Similar in form to that of House-fly, but more trans-
lucent in appearance. Duration 10-20 days.

Pupa. — Duration 6-20 days; puparium reddish-brown, elongate-
oval, }i inch long.

This fly occurs in the open, but often enters houses; breeds rapidly
in oat-straw and other organic refuse. Winters as pupa or larva.

Control. — Apply 0.62 lb. borax to every 10 cu. ft. (8 bushels) manure,
on removal from stables, with a flour sifter or fine sieve, particularly
about the edges of the pile, and sprinkle 2 or 3 gal. water over the
heated manure; use fly-traps. (Consult Farmers' Bulls. 540, 734 and
851, U. S. Dep. Agr., 1913.)

Horn Fly {Hcematobia serrata ^oh. -T>es,v.,Lyperosia irritans'Lm.n.) . —
(Consult Circ. 115, Bur. Ent., U. S. Dep. Agr.) Introduced into
U. S. about 1886 from Europe, and has spread rapidly since.

Adult. — Similar in shape and color to House-fly, but about half as
large. June-September.

Eggs. — ^Laid singly in fresh cow manure in day time, irregular, oval,
light reddish brown. Egg-laying begins soon after adult emerges.

Larva. — White, 14 i^^ch long; full grown in 4-6 days.

Pupa. — Puparium dark brown, ellipsoidal, 36 i^^h long; pupal
stage lasts 5-10 days.

Probably 6-8 generations in a season.

Control. — (i) Killing the maggots by the introduction into the man-
ure of Hme and other drying and destructive agents; (2) application of
creolin compounds in the form of spray, or kerosene emulsion solution,
or a mixture of 3^^ gal. fish oil, Yi pint coal oil, 4 tbspfls. crude carbolic
acid applied with a cloth rubbed over the parts attacked.

The main factors limiting the number of the common flies are:

(a) The destruction of the larvae and pupae by braconid and chalcid
parasites;

{h) The lack of food for the larvae;

(c) The enemies of the adults;

{d) Weather conditions — oppressive sultry weather; cold, wet
and windy weather; acting on the adults, and preventing the emergence
of adults from the pupae.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 273

The Screw-worm Fly {Chrysomyia macellaria Fab.) occurs as far
north as Canada but is of importance economically in the south-
western States as a pest of stock. The adult is larger than the house-fly,
of a dark bluish-green color, with three distinct black stripes on the
thorax. The eggs are laid in irregular masses upon dead animals and
in wounds. The maggots bore into the carcass or flesh, often causing
death. (See Farmers' Bull. 857, U. S. Dep. Ag.)

Blue Bottle or Green Bottle Flies. — -Two or three common species
of these flies occur which are also known as Blow, Green or Blue
Bottle FHes.

Meat Fly, or Blue Bottle, or Blow Fly {Calliphora vomitoria Linn.). — •
A large blackish fly with bluish abdomen and black spines on the thorax.
Its eggs are laid on meat and dead animals, and each female may lay 400
to 600 eggs, which hatch very soon after deposition. Duration of a gen-
eration 22 to 23 days. C. erythrocephala Meig. is another common
species with a pre-oviposition period of 12-17 days, an active larval
stage of 3-4 days and a pupal stage of 7-9 days.

Green Bottle Fly (Lucilia ccBsar Linn.). — Similar in habits to Meat
Fly, with pre-oviposition period of 1-3 weeks, active larval stage of 2-5
days and a pupal stage of 5-16 days. Hibernates as larva and pupa.

Phormia regina Meig. is a large black fly seen in early spring in
houses, and breeds in garbage.

Large Blue Bottle Fly {Cynomyia cadaverina Desv.) frequents
pantries. Lays eggs on meats — smoked, uncured and cooked. Pre-
oviposition period i to 3 weeks, larval period 5-40 days, and pupal
stage 1-8 weeks.

The Cluster Fly {Pollenia rudis Fabr.) and Muscina stabulans Fall,
are also dangerous as disease carriers (see Part I). The former is
found in early spring and late autumn crawling sluggishly about,
often collecting in large numbers in and about houses. It has short
curly yellow hair on dorsum of thorax. Probably breeds in manure
and garbage.

ANTHOMYIDiE (ANTHOMYIDS)

Root Maggots {Phorbia spp.). — Three spec'es of root maggots are
commonly injurious to root crops — Cabbage Root Maggot, Onion
Maggot and Seed Corn Maggot.

Cabbage Root Maggot {Phorbia brassicce Bouche). — A widely dis-
tributed insect, introduced from Europe.

18

2 74

ECONOMIC ENTOMOLOGY

Adult. — Smaller than House-fly; He inich long; greyish, with three
blackish, rather broad bands on back of thorax and a dark stripe along
back of abdomen; a number of stiff hairs on body and legs; eyes red-

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Fig. 175. — Male of the cabbage root maggot fly. Enlarged about 3 times.
(Photo by J. T. Wadsworth. After Gibson and Treherne, Bui. 12, Ent. Br.
Dept. Agric. Ottawa.)

Fig. 176. — Female of the cabbage root maggot fly,. Enlarged about 3 times.
(Photo by J. T. Wadsworth.) After Gibson and Treherne, Bui. 12, Ent. Br.
Dept. Agric. Ottawa.)

dish-purple. Hibernates sometimes as adult. Pre-oviposition period
about 6 days (Figs. 175 and 176).

Eggs. — Elliptical, white, ^^5 inch long; 50-60 deposited separately
on the surface of ground or on stem of plant; stage lasts about a week.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 275

Larva. — A whitish, cylindrical, footless maggot, tai)ering toward
the front, and abruptly terminated behind, where are 12 two-pointed
fleshy tubercles and 2 conspicuous reddish-brown spiracles; 3^:4 inch
long when full grown (3 to 4 weeks) (Figs. 177 and 178).

Pupa. — Puparium in earth, oval, 3^^ inch long, chestnut-brown;
2 weeks in June; hibernates.

Pig. 177. — (a) Caudal end of cabbage root maggot; {h) of the imported
onion maggot; and (c) of the seed-corn maggot; showing arrangement of fleshy
tubercles and central spiracles. All much enlarged. {After Gibson and Treherne,
Ent. Bui. 12, Dept. Agric. Ottawa.)

Life-history. — Adults appear in May, when cabbages are being set
out, and deposit eggs. Maggots hatch in a week and feed on roots
for 3 or 4 weeks when they change to pupae within puparia in
the soil. In 15 days or so the adults appear in late June and July
to lay eggs for a second brood. The number of broods is uncertain,
probably three or four, but the later broods do but little harm.

Fig. 178. — Cabage root maggot, side view. Enlarged 7 times. {After Gibson and
Treherne, Ent. Br. Can.)

Control. — Use "single-ply tarred felt" paper disks when young
plants are set out; use cheese cloth frames as screens; plant trap-crops;
apply white hellebore or pyrethrum either as dust or as solution;
use carbolic wash; use corrosive sublimate solution (4 oz to 50
gal. water). In the case of the last three insecticides, treatment
should be made when the plants are set out and repeated once a week
for 5 weeks.

Enemies. — Baryodma ontarionis, a Staphylinid; Cothonaspis gillettei
Wash., a Cynipid; and Trombidium spp. — (Consult Bull. 12, Ent. Br.

276

ECONOMIC ENTOMOLOGY

Dep. Agr. Canada, 1916; Bull. 419, N. Y. Agr. Exp. Stn.; Cornell Univ.,
Bull. 78.)

Onion Maggot {Phorbia ceparum Mg. = Hylemyia antiqua Mg.).
Adult. — Slightly larger than Cabbage Root Maggot Fly; body and
legs with many black bristles; back of thorax of male with four indistinct
dark colored bands; abdomen with a distinct blackish band down
the middle; May-June. Probably three broods a year. Pre-oviposi-
tion period about 10 days (Fig. 180).

Fig. 179. — Onion maggot (Phorbia ceparum), female and head of male.

Eggs. — Cylindrical, white, distinctly ridged; groove not so deep or
long as in P. brassicce; duration 3 to 4 days.

Larva. — White, cylindrical, rounded, truncate at posterior end;
^5 inch long; central tubercles of blunt end single-pointed, with a pair
of additional tubercles. Duration 2-3 weeks, occasionally 4-5 weeks.
Young larva works its way down within the sheath of the plant to the
forming bulb, in which it feeds.

Pupa. — Puparia formed in soil or in outer layers of onion. Found
13^^-3 inches below the surface. Summer duration about 2 weeks;
hibernates.

CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 277

The Barred-winged Onion Maggot {Chaitopsis oenea Wied.) is also
injurious to onions (Michigan).

Control. — Apply poisoned bait spray composed of sodium arsenite
and molasses to kill adults; apply hellebore, pyrethrum and carbolic
wash.

Seed Com Maggot (PhorbiafuscicepsZett.). — (Consult Bull. 12, Ent.
Br. Dep. Agric. Can.). Injurious frequently to beans, peas and corn.

Adult. — Smaller than Onion Maggot Fly, }-^ inch long; bands on
back of thorax indistinct, those on abdomen distinct; inner side of pos-
terior tibiae of male with a row of short bristly hairs. Body of female
pointed, eyes widely separate. June-July.

Eggs. — ^Laid on or about the seed in the soil, or on the seedling.

Larva. — Smaller than Cabbage Root Maggot or Onion Maggot, 3^^
inch long; whitish, cylindrical, footless, blunt at caudal end and pointed
at the head. Caudal tubercles simple, rather close together with a
trace of additional tubercles. Feeds mostly on the seed.

Pupa. — Puparium }i inch long, light brown to dark reddish-brown;
duration 12 days.

Number of generations not yet known. Injury seems most severe
when a wet period follows immediately after planting the seed.

Control. — Difl&cult. Use mineral fertilizers; carbolic acid emulsion.

Raspbeny Cane Maggot (Phorbia rubivora Coquillet). Adult. — A
grayish-black fly, smaller than the house-fly. April.

Eggs. — White, elongate, 3^^ 5 inch long, laid in the axil of young
leaves at the tip of shoot. Hatch in a few days.

Larva. — Maggot bores into the pith of the shoot, and tunnels
downward, making a tortuous path. About halfway down it girdles
the wood beneath the bark. It continues burrowing downward and
becomes full grown in June. Wilting occurs in May.

Pupa. — Formed at lower end of burrow in June and July.

Control. — Cut off and burn the wilting canes as soon as observed.

Beet Leaf Miner {Pegomyia vicina Lintner). — It is sometimes de-
structive to beets in late fall. Whitish blotches are formed on the
leaves. There are several generations each year, and the winter is
passed in the pupal condition under fallen leaves or in the soil. The
eggs are placed on the lower side of the leaves, and the maggots mine
in the leaves; life-cycle about a month.

Control. — Pick and burn infested leaves where practicable; use

2 78

ECONOMIC ENTOMOLOGY

spinach as a trap crop; plow deep and harrow as soon as crop is
removed.

Lesser House-fly {Homalomyia canicularis Linn.). — This fly is
smaller than Musca domestica, and may be observed in houses in early
summer. As an Anthomyiid it can be readily distinguished from the
true muscids by